Abstract
Estimates of venous thromboembolism (VTE) incidence in the United States are limited by lack of a national surveillance system. We implemented a population-based surveillance system in Oklahoma County, OK, for April 1, 2012 to March 31, 2014, to estimate the incidences of first-time and recurrent VTE events, VTE-related mortality, and the proportion of case patients with provoked versus unprovoked VTE. The Commissioner of Health made VTE a reportable condition and delegated surveillance-related responsibilities to the University of Oklahoma, College of Public Health. The surveillance system included active and passive methods. Active surveillance involved reviewing imaging studies (such as chest computed tomography and compression ultrasounds) from all inpatient and outpatient facilities. Interrater agreement between surveillance officers collecting data was assessed using κ. Passive surveillance used International Classification of Disease, Ninth Revision (ICD-9) codes from hospital discharge data to identify cases. The sensitivity and specificity of various ICD-9–based case definitions will be assessed by comparison with cases identified through active surveillance. As of February 1, 2015, we screened 54,494 (99.5%) of the imaging studies and identified 2,725 case patients, of which 91.6% were from inpatient facilities, and 8.4% were from outpatient facilities. Agreement between surveillance officers was high (κ ≥0.61 for 93.2% of variables). Agreement for the diagnosis of pulmonary embolism and diagnosis of deep vein thrombosis was κ = 0.92 (95% CI 0.74-1.00) and κ = 0.89 (95% CI 0.71-1.00), respectively. This surveillance system will provide data on the accuracy of ICD-9–based case definitions for surveillance of VTE events and help the Centers for Disease Control and Prevention develop a national VTE surveillance system.
The US Surgeon General’s 2008 “Call to Action to Prevent Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE)”1 raised the importance of conducting surveillance for venous thromboembolism (VTE). Current estimates of the burden of VTE in the United States (350,000-900,000 events and 100,000-300,000 deaths annually) come from 2 principal sources. The first is cohort studies in selected counties and then generalized to the US population.2,3 The second is administrative claims data.4-8 Both of these methods have limitations. The estimates from the cohort studies come from a largely white population and may not be representative of the diversity of the US population. Although the inclusion of present on admission (POA) codes has increased the positive predictive value of International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9 CM) codes to identify inpatient VTE cases,6 there are remaining limitations in using administrative data to document cases of VTE because (1) coding may reflect old diagnoses that are no longer active diagnoses, (2) coding practices vary between facilities, (3) the inability of deidentified data to differentiate between incident and recurrent events and between incident events and duplicate events caused by patient transfers, (4) the inability to determine dates of diagnosis (traditionally based on facility discharge dates), (5) nonhospitalized patients and those who had sudden death from PE have usually not been included in these estimates, and (6) the ideal case definition using selected ICD-9 CM codes has not been established given the varying performance of VTE-related ICD-9 CM codes.
In addition to removing the uncertainty in the estimates of VTE incidence, other aspects of the epidemiology of VTE disease would also be informed by improved surveillance. For example, it is difficult to differentiate between provoked and unprovoked events. Although certain strong risk factors have been well established, such as surgery, hospitalization, and cancer, a large number of patients experience VTE in the absence of an identifiable risk factor (ie, unprovoked VTE). The racial and ethnic distribution of VTE events in the United States, for both provoked and unprovoked events, remains incompletely understood. In addition, contemporary data are needed on the utilization of appropriate prophylaxis against VTE in patients at risk and to document the proportion of VTE events, which may have been potentially preventable.
Venous thromboembolism is a condition well suited for surveillance using modern techniques and diagnostic imaging. Because a diagnosis of DVT or PE based solely on the evaluation of clinical signs has proven unreliable, imaging studies are required for accurate diagnosis.9 Noninvasive and highly sensitive and specific diagnostic procedures, including computed tomography angiography (CTA) for PE and compression ultrasound (CUS) for DVT, are routinely used in clinical practice for the diagnosis of VTE. Thus, the College of Public Health at the University of Oklahoma Health Sciences Center, in collaboration with the Centers for Disease Control and Prevention (CDC), the Oklahoma State Department of Health, and the Oklahoma City–County Health Department, established a novel pilot population-based surveillance system for VTE events in Oklahoma County, OK, from April 1, 2012 to March 31, 2014. Oklahoma County was suitable for this pilot testing because of the strong similarity of its population demographics to the US national population. We describe this novel surveillance approach for VTE events using combined active and passive surveillance and discuss how these methods may inform the development of a national surveillance system as well as contribute to increased understanding of the burden of VTE disease.
Methods
Surveillance system objectives
The primary aims of our pilot surveillance system were to (1) develop and implement a population-based surveillance system for DVT and PE in Oklahoma County, OK, that includes both active and passive surveillance activities and which can accurately capture outpatient, inpatient, and death-related VTE events and distinguish first episode (incident) from recurrent VTE events; (2) estimate the annual incidence of first-episode VTE events and DVT and PE separately, (3) estimate the annual incidence of recurrent VTE events and of the components of DVT and PE, (4) estimate the 30-day, 90-day, and 6-month mortality associated with a diagnosis of VTE and the component events of DVT or PE; (5) describe the above VTE disease burden indicators by age, gender, and race/ethnicity, including the minority groups of American Indian, Black, Hispanic, and Asian; (6) collect data on risk factors associated with documented VTE events; and (7) identify hypotheses for future research to reduce the burden of VTE disease (see Table I).
Table I.
Objectives for the VTE surveillance system using combined active and passive methods
| Objectives |
|---|
|
Surveillance system and population
A key and unique feature of this surveillance system is the collaboration with the Oklahoma State Commissioner of Health, who established VTE diagnoses as reportable conditions for 2010 to 2015 and delegated to the College of Public Health the authority to conduct the surveillance (Oklahoma Statute §631-106B). The surveillance was conducted as an activity authorized by federal10 and state statutes for protection of public health, and, therefore, institutional review board approval for access to the health information was not required. The surveillance was conducted in compliance with the requirements of the US Health Insurance Portability and Accountability Act.
Oklahoma County is representative of the US population by race and ethnicity (Table II), although it has a higher percentage of American Indians (7.7% vs 1.7%).11 In addition, it is an urban metropolitan service area in the center of the state for which few residents travel out of the county or the state for their health care. Hospital discharge data (described in detail below) for the state were accessed to determine that 98 Oklahoma County residents received care for a VTE-related event out of Oklahoma County during 2010 to 2012.
Table II.
Racial, ethnic, gender, and income distribution of the population in the United States, Oklahoma State, and Oklahoma County, 201211
| United States |
Oklahoma County |
|||
|---|---|---|---|---|
| Race/ethnicity | n | % | n | % |
| Population | 313,914,040 | 100 | 741,781 | 100 |
| Race | ||||
| White | 239,645,013 | 76.3 | 553,227 | 74.6 |
| Black | 43,140,238 | 13.7 | 127,854 | 17.2 |
| American Indian | 5,226,034 | 1.7 | 57,462 | 7.7 |
| Asian | 18,326,450 | 5.8 | 28,223 | 3.8 |
| Hawaiian/Pacific Islander | 1,250,274 | 0.4 | 1,500 | 0.2 |
| Other | 16,232,503 | 5.2 | 26,956 | 3.6 |
| Ethnicity | ||||
| Hispanic | 52,961,017 | 16.9 | 116,932 | 15.8 |
| Non-Hispanic | 260,953,023 | 83.1 | 624,849 | 84.2 |
| Gender | ||||
| Male | 154,436,243 | 49.2 | 363,306 | 49.0 |
| Female | 159,477,797 | 50.8 | 378,475 | 51.0 |
| Median income (dollars) | 53,046 | 45,082 | ||
We implemented both active and passive surveillance methods in an effort to quantify and measure the extent to which each approach successfully identified cases. The active surveillance system was designed to serve as the criterion standard and to optimize specificity. The passive surveillance system was designed to optimize sensitivity. The Figure is a flowchart of all surveillance activities.
Figure.
Flowchart for surveillance system for VTE in Oklahoma County, OK—April 1, 2012 to March 31, 2014. Abbreviations: ASC, ambulatory surgical centers; IP, inpatient; OP, outpatient; HCI, health care information; ID, identification.
Active surveillance
Active surveillance consisted of surveillance officers (graduate students in public health generally with clinical backgrounds) visiting all of the 13 inpatient facilities and all of the eligible outpatient facilities in Oklahoma County on a regular basis. Criteria for eligible inpatient and outpatient facilities are summarized in Table III. Surveillance officers reviewed the text of relevant imaging reports from April 1, 2012 to March 31, 2014, to classify VTE cases as definite or probable cases or noncases (see case definition, Table IV). We also included the Oklahoma City Veterans Affairs (VA) Medical Center. Eligible facilities were identified by using 3 different data sources: (1) historic hospital discharge data (2009-2010) to estimate the potential caseload; (2) the Oklahoma State Health Department’s database of facilities licensed for CTA, magnetic resonance imaging (MRI), and CUS equipment in the county; and 3) the national accrediting body of facilities using those same diagnostic equipment. Before initiating surveillance, we met with the Greater Oklahoma City Hospital Council and introduced the surveillance project to the chief executive officers of the county’s hospitals. We also communicated with each inpatient and outpatient facility by mail and telephone. We met with the health information management director of each facility to establish surveillance activities, provide them with the case definition, and tailor our case methods to their facility processes. We screened outpatient facilities for eligibility based on the relevant diagnostic equipment they used and whether they diagnosed patients with VTE conditions.
Table III.
Inpatient and outpatient facility inclusion criteria
| Inpatient and outpatient | |
|---|---|
| Inclusion criteria |
|
| Exclusion criteria |
|
Table IV.
Case definitions for DVT and PE
| DVT | PE | |
|---|---|---|
| Definite |
|
|
| Probable |
|
|
| Possible: ≥2 of the following: |
|
|
Each facility (both inpatient and outpatient) generated lists of all patients who had received one of the qualifying imaging studies (irrespective of the radiologists’ diagnosis) or a diagnostic or procedure code (online Appendix A and B) during the surveillance period, regardless of the patient’s symptoms. Because of varying medical records systems, facilities used a variety of methods to identify these patients, including querying their system for ICD-9 CM procedure codes, current procedural terminology (CPT) codes, and free text for the test (such as “CTA” or “ultrasound”). We worked with a variety of electronic medical records systems, including Cerner, Centricity, Meditech (Horizon Patient Folder), and EPIC as well as a few facilities still using paper-based records.
Patient records were retrieved by facility staff and reviewed by surveillance officers to identify those whose residence was within Oklahoma County (as determined by county and ZIP code information) for inclusion in the surveillance. Subsequently, the surveillance officers determined eligibility based on the occurrence of a VTE event during the surveillance period (April 1, 2012 to March 31, 2014), which was followed by review of the final impression from the imaging report and complete data abstraction of eligible cases. Screening the imaging report for a PE or DVT diagnosis required approximately 1 minute per record, and data abstraction typically required 45 to 60 minutes per record. Data abstraction included patient-identifying information, demographic variables, medical history (including history of VTE), signs and symptoms related to their VTE diagnosis, major and minor risk factors, and VTE prophylaxis and treatment, including medication regimens and dates administered.
We collected data on age, gender, race (defined as white, black, American Indian, Asian, Pacific Islander, and other) and ethnicity (defined as Hispanic and non-Hispanic), obesity (measured by height and weight), hospitalization, surgery or trauma within the prior 12 months, cancer (except basal or squamous cell carcinoma of the skin), paralysis of the leg, pregnancy, myocardial infarction, stroke, systemic lupus erythematosus, and inflammatory bowel disease. Reason for hospitalization and indication for and type of surgery were also collected. Dates for each risk factor were collected when available, and, when unavailable, any data regarding time frame were collected and categorized into <3 months, 3 to 5.9 months, 6 to 11.9 months, and ≥12 months.
Surveillance officers entered case-patient data directly into Velos eResearch using encrypted laptops with secure internet connections. The Velos-based database was housed behind the university’s information technology firewall, and the case-patient data were securely stored and compliant with the Health Insurance Portability and Accountability Act regulations. We limited the use of paper-based records to increase security as well as efficiency of data entry.
Passive surveillance
Passive surveillance consisted of acquiring all-payer hospital discharge data (with patient-identifying information) from the Oklahoma State Department of Health’s Division of Health Care Information. Because the VA is not required to report to state agencies, their data are not included in the hospital discharge data. The ICD-9 CM codes used in this system are listed in the online Appendix A and B. We were able to access and use patient-specific data because the State Health Commissioner delegated to the College of Public Health the authority to conduct the surveillance (Oklahoma Statute §631-106B).
We obtained hospital discharge data with patient identifiers from all inpatient, outpatient, and ambulatory surgery center facilities for all cases diagnosed and treated in Oklahoma County and all events associated with that individual for each year 2010 to 2012 using our broad VTE definition (online Appendix A and B) (2013-2014 data will be obtained when available). Cases were identified by using either the primary ICD-9 CM diagnosis field or any of the 15 contributing ICD-9 CM diagnosis fields.
We also received the January 1, 2010 to April 30, 2014, mortality files compiled from death certificates (subsequent years will be obtained upon availability). Cases were identified using ICD-10 codes and text in the cause of death and significant contributing causes of death fields (online Appendix A and B).
The data were merged and deduplicated within and across years, between discharge types (ie, inpatient, outpatient, and ambulatory surgical care), and across data types (ie, hospital discharge data and mortality data) using Link Plus,12 a probabilistic record linkage software designed to link records with incomplete or variable information according to patient-identifying information (name, date of birth, address, and social security number). The probabilistic linkage algorithm assigns probability scores that indicate how likely it is that a pair of records refer to the same person. A threshold score of 3 was used to automatically accept and reject potential links with all uncertain pairs manually reviewed by 2 independent reviewers. Once complete, 2 manual reviews were compared to confirm or reject matches.
Case definition
We used tiered case definitions and case finding methods based on the amount and quality of the diagnostic data available as shown in Table IV. All DVT events of the upper and lower extremities are included, including acute, chronic, and recurrent. Superficial venous thromboses were excluded. For active surveillance, a finding of DVT or PE based on an imaging study including CTA, CUS, MRI, ventilation-perfusion (V/Q) scan, or pulmonary angiogram was required for either a definite or probable case. Final case classification was assigned by study investigators (see interrater reliability below). Furthermore, patients were classified as a probable case when the death certificate listed PE as a primary or contributing cause of death.
Passive surveillance relied on ICD-9 CM (diagnosis and procedure), CPT, or POA codes for identification of possible VTE events. Thus, the only case classification available was as a possible case (in which ≥2 qualifying codes were required). The full case definition is included in the appendix.
Comparing active with passive surveillance
Once available, the passive surveillance data (ie, hospital discharge data and mortality data) will be linked to the active data and deduplicated using probabilistic record linkage methods similar to those described in the passive surveillance above. In addition, we will use the same method to link live cases identified using active surveillance to the mortality file.
Statistical methods
Descriptive statistics were used to summarize population demographics. The distribution of case patients for each stage of surveillance and disease manifestation was presented for each facility type (inpatient vs outpatient). All analyses were conducted using SAS 9.3 (SAS Institute, Inc, Cary, NC).
Interrater reliability for data collection was evaluated by taking a random sample of 5% (with a minimum of 5 records per facility) of the cases that were identified from 7 inpatient facilities and selected for quality assurance. At least 2 secondary surveillance officers independently collected data for each identified case, and agreement was assessed (using the κ statistic) between the primary surveillance officer and the 2 secondary reviewers.
We used the free marginal method13 to calculate κ to assess agreement for all categorical variables. Agreement was categorized into very good (κ = 0.81-1.0), good (κ = 0.61-0.80), moderate (κ = 0.41-0.60), and poor to fair (κ ≤0.40).
Funding was provided through a cooperative agreement (DD14-1407) with the CDC for the design and implementation of the surveillance system and publication of the design manuscript. The authors are solely responsible for the design and conduct of this study; all study analyses, the drafting and editing of the paper, and its final contents.
Results
All 13 inpatient facilities in Oklahoma County and the Oklahoma City VA Medical Center were included in this surveillance system. Fifty-six outpatient facilities were identified as being potentially eligible for surveillance; however, after contacting each facility, only 8 facilities met the criteria to be included in the surveillance, each of which contributed data to the surveillance system. As of February 1, 2015, we have screened 54,494 (99.5%) of 54,782 identified imaging records of patients having had one of the diagnostic procedures (ie, CTA, MRI, V/Q scan, and CUS) during the surveillance period (Table V). From the records screened, we have identified 2,725 case patients with VTE using the active surveillance system (of which 2,496 [91.6%] case patients are from inpatient facilities and 229 [8.4%] case patients are from outpatient facilities). Among the 2,231 case patients for whom data collection is complete, 1,290 (63%) have DVT, 476 (23%) have PE, and 293 (14%) have both DVT and PE. In addition, among the 172 (7.7%) case patients enrolled from outpatient facilities for whom data collection has been completed, 156 (91%) case patients have DVT, 11 (6%) case patients have PE, and 5 (3%) case patients have both DVT and PE (Table VI). Using hospital discharge data for 2010 to 2012, we identified 98 residents (2.4% of the case patients) of Oklahoma County who received a diagnosis for a VTE-related event outside Oklahoma County who were missed by the active surveillance.
Table V.
The distribution of case patients for each stage of surveillance stratified by facility type
| Identified patients with diagnostic procedure |
Screened records |
Patients meeting case definition |
Case patients with data collection complete |
|||||
|---|---|---|---|---|---|---|---|---|
| Facility type | n | % | n | % | n | % | n | % |
| Inpatient facilities | 50,535 | 92.2 | 50,466 | 92.6 | 2496 | 91.6 | 2059 | 92.3 |
| Outpatient facilities | 4247 | 7.8 | 4028 | 7.4 | 229 | 8.4 | 172 | 7.7 |
| Total | 54,782 | 100 | 54,494 | 100 | 2725 | 100 | 2231 | 100 |
Table VI.
The distribution of case patients stratified by facility type and disease manifestation
| Inpatient facilities |
Outpatient facilities |
Total |
||||
|---|---|---|---|---|---|---|
| Disease manifestation | n | % | n | % | n | % |
| VTE cases | 2059 | 100 | 172 | 100 | 2231 | 100 |
| DVT only | 1290 | 62.7 | 156 | 90.7 | 1446 | 64.8 |
| PE only | 476 | 23.1 | 11 | 6.4 | 487 | 21.8 |
| Both DVT and PE | 293 | 14.2 | 5 | 2.9 | 298 | 13.4 |
Our data collection instrument had 44 variables. Agreement between data collectors was high, with 41 (93.2%) variables having κ, ≥0.61. The agreement for our 2 key measurements, diagnosis of PE and diagnosis of DVT, were κ = 0.92 (95% CI 0.74-1.00) and κ = 0.89 (95% CI 0.71-1.00), respectively. The 3 variables with moderate agreement were symptoms of the leg (κ = 0.59; 95% CI 0.42-0.77), history of DVT (κ = 0.59; 95% CI 0.42-0.77), and history of hospitalization (κ = 0.45; 95% CI 0.27-0.62). The agreement between the 2 study investigators’ classification of cases according to the case definition was also high, DVT, κ = 0.84 (95% CI 0.76-0.93) and PE, κ = 0.94 (95% CI 0.88-1.00).
Discussion
We established a pilot population-based surveillance system for VTE using both active and passive methods in Oklahoma County, OK, to inform CDC regarding the development of future national VTE surveillance. We designed this system to (1) improve VTE-related estimates of the incidence of first-time and recurrent events and mortality rates, (2) differentiate between provoked and unprovoked events as well as describe these patients by demographic characteristics (including race/ethnicity), and (3) identify the contribution of patients with VTE events in the outpatient setting.
This surveillance system has been operating as intended as evidenced by the progress made in identifying potential case patients, applying the case definition, and collecting the demographic and diagnostic information regarding the VTE event. Among the 54,670 patients flagged for screening based on having a diagnostic procedure during the surveillance period, 99.6% have been screened. In addition, data have been collected for >80% of all identified cases. This amount of progress lends confidence to the continued success of the surveillance system through the end of the surveillance period.
This pilot surveillance system was not designed to be sustainable in its present form. Instead, we designed it to inform us and CDC regarding the performance of each aspect of VTE disease surveillance. However, without a standard by which to assess the performance of hospital discharge and administrative claims data, the sensitivity and specificity of a national surveillance system will be unknown. Hence, the active surveillance was developed to serve as the criterion standard by maximizing specificity through the use of imaging studies to confirm and classify cases. On the other hand, because ICD-9 CM codes have the tendency to “follow” patients over time, querying the hospital discharge database is a highly sensitive technique for identifying possible cases. Sensitivity was further enhanced by using a broad set of codes designed to maximize the identification of possible cases. The final step of linking the active and passive surveillance databases by patient-identifying information and then investigating the discordant cases will allow us to assess the performance (ie, sensitivity, specificity, and positive predictive values) of case definitions based on ICD-9 CM codes. We will also be able to evaluate the ability of our active system to detect cases by sampling those possible cases from the hospital discharge data who did not link to the active cases and following up back to determine if they were a true case missed by our active methods or a false-positive based on using ICD-9 CM codes. Using the cleaned, deduplicated, linked database, we will be able to provide estimates of first-time and recurrent VTE events that are likely more accurate than any that are currently available by claims data.
Another strength of this system will be the ability to better describe risk factors for VTE events and to differentiate between provoked and unprovoked events. Among the case patients with provoked VTE events, we will be able to measure the utilization of VTE prevention measures and identify points of intervention to improve the implementation of prevention if needed. This may improve our ability to identify a certain proportion of potentially preventable cases (which could be used as a performance metric for hospitals in the future). Finally, given the racially diverse population in Oklahoma County, we aim to be able to describe the incidence and risk factors in minority populations that have been historically understudied.
The last objective of our surveillance system is to determine the number of patients with VTE events being diagnosed and/or managed in an outpatient setting. The barriers to outpatient management of VTE in the United States include (1) initial treatment has traditionally consisted of parenteral therapy, which is easier to administer in the hospital,14 (2) remuneration for health care facilities and providers is higher in an inpatient setting,15,16 and (3) the patient population often has comorbid conditions requiring inpatient care. On the other hand, a factor which may increase the outpatient management of VTE is the development of new oral medications.14,17 Our finding that approximately 8% of patients were diagnosed in the outpatient setting is lower but similar to 11% in a German retrospective cohort study. 18 By conducting active surveillance in outpatient facilities with CT and CUS machines, we will be able to better understand the proportion of patients referred to tertiary care facilities for further treatment and care and thus inform future scaled-up national surveillance regarding the importance of including outpatient facilities.
Our surveillance system is subject to certain limitations. One limitation is the time lag between the hospitalization and when the hospital discharge data are available for the passive surveillance. Specifically, the hospital discharge data are not available until approximately 1 year after the end of that discharge year. In contrast, the active data are typically delayed by no more than a month (while waiting for the patient to be discharged and all the data to be entered into the facility’s electronic medical record). Thus, the data collected by active and passive methods cannot be linked and analyzed until ≥1 year after the event. Other limitations include the cost involved to conduct active surveillance (which is unlikely to be maintained over long periods), missing risk factor information in the medical record, variability in the way facilities identify potentially eligible patients for screening, and the amount of time required for surveillance officers to screen potentially eligible patients and subsequently enter their information into the database.
Additional limitations include factors contributing to us potentially missing a VTE case. One scenario is those patients who seek and are diagnosed outside the catchment area (ie, Oklahoma County). We will, however, include these cases if they receive follow-up care within the catchment area during the surveillance window. Another scenario is those VTE cases that never had the relevant imaging studies, did not have an eligible ICD-9 code, and, for those who died, had no mention on the death certificate. Finally, although the demographics of Oklahoma County are remarkably similar to the US national population, there may be other features of our surveillance population, which may not be generalizable to the US population. This latter limitation is the key reason why a national surveillance system is required. Although incidence estimates derived from a population-based study restricted to a county or state may have limitations in generalizability, the methods evaluated in the pilot study should be scalable for use in a broader national effort.
Conclusions
In conclusion, we developed a pilot population-based surveillance system for VTE in Oklahoma County, OK. This novel system incorporates both active and passive elements. The most important factor in conducting our surveillance was the collaboration with CDC and the Oklahoma Commissioner of Health. This allowed us to work with all facilities in the county and collect the required information. We are in the process of better understanding the quality of individual ICD-9 CM codes in identifying true cases. In addition, these results will help inform future national surveillance and monitoring for VTE events. Future topics we plan to address using these data include identifying the proportion of preventable VTE events, better elucidating the incidence of provoked versus unprovoked events, and describing the extent to which patients receive the evidence-based recommended treatment for their VTE condition.
Acknowledgments
This surveillance system was funded by a cooperative agreement with the CDC DD14-1407. We are also deeply grateful for the work of the surveillance officer, Natalie Feland, Aubrey Balch, Jannate Ahmed, Evaren Page, and Ashley Sword-Buster, for their tireless dedication in collecting the data. We are also grateful for Pravina Kota for her information technology support, including the development of the database.
CDC disclaimer: The findings and conclusions in this report are those of the author(s) and do not necessarily represent the official position of the CDC.
Appendix A
Deep vein thrombosis—related ICD-9 codes, CPT codes, and ICD-10 codes
|
ICD-10 codes |
Definition |
|---|---|
| I80 | Phlebitis and thrombophlebitis |
| I800 | Phlebitis and thrombophlebitis of superficial vessels of lower extremities |
| I8000 | Phlebitis and thrombophlebitis of superficial vessels of unspecified lower extremity |
| I8001 | Phlebitis and thrombophlebitis of superficial vessels of right lower extremity |
| I8002 | Phlebitis and thrombophlebitis of superficial vessels of left lower extremity |
| I8003 | Phlebitis and thrombophlebitis of superficial vessels of lower extremities, bilateral |
| I801 | Phlebitis and thrombophlebitis of femoral vein |
| I8010 | Phlebitis and thrombophlebitis of unspecified femoral vein |
| I8011 | Phlebitis and thrombophlebitis of right femoral vein |
| I8012 | Phlebitis and thrombophlebitis of left femoral vein |
| I8013 | Phlebitis and thrombophlebitis of femoral vein, bilateral |
| I802 | Phlebitis and thrombophlebitis of other and unspecified deep vessels of lower extremities |
| I8020 | Phlebitis and thrombophlebitis of unspecified deep vessels of lower extremities |
| I80201 | Phlebitis and thrombophlebitis of unspecified deep vessels of right lower extremity |
| I80202 | Phlebitis and thrombophlebitis of unspecified deep vessels of left lower extremity |
| I80203 | Phlebitis and thrombophlebitis of unspecified deep vessels of lower extremities, bilateral |
| I80209 | Phlebitis and thrombophlebitis of unspecified deep vessels of unspecified lower extremity |
| I8021 | Phlebitis and thrombophlebitis of iliac vein |
| I80211 | Phlebitis and thrombophlebitis of right iliac vein |
| I80212 | Phlebitis and thrombophlebitis of left iliac vein |
| I80213 | Phlebitis and thrombophlebitis of iliac vein, bilateral |
| I80219 | Phlebitis and thrombophlebitis of unspecified iliac vein |
| I8022 | Phlebitis and thrombophlebitis of popliteal vein |
| I80221 | Phlebitis and thrombophlebitis of right popliteal vein |
| I80222 | Phlebitis and thrombophlebitis of left popliteal vein |
| I80223 | Phlebitis and thrombophlebitis of popliteal vein, bilateral |
| I80229 | Phlebitis and thrombophlebitis of unspecified popliteal vein |
| I8023 | Phlebitis and thrombophlebitis of tibial vein |
| I80231 | Phlebitis and thrombophlebitis of right tibial vein |
| I80232 | Phlebitis and thrombophlebitis of left tibial vein |
| I80233 | Phlebitis and thrombophlebitis of tibial vein, bilateral |
| I80239 | Phlebitis and thrombophlebitis of unspecified tibial vein |
| I8029 | Phlebitis and thrombophlebitis of other deep vessels of lower extremities |
| I80291 | Phlebitis and thrombophlebitis of other deep vessels of right lower extremity |
| I80292 | Phlebitis and thrombophlebitis of other deep vessels of left lower extremity |
| I80293 | Phlebitis and thrombophlebitis of other deep vessels of lower extremity, bilateral |
| I80299 | Phlebitis and thrombophlebitis of other deep vessels of unspecified lower extremity |
| I803 | Phlebitis and thrombophlebitis of lower extremities, unspecified |
| I808 | Phlebitis and thrombophlebitis of other sites |
| I809 | Phlebitis and thrombophlebitis of unspecified site |
| I82 | Other venous embolism and thrombosis |
| I821 | Thrombophlebitis migrans |
| I822 | Embolism and thrombosis of vena cava and other thoracic veins |
| I8221 | Embolism and thrombosis of superior vena cava |
| I82210 | Acute embolism and thrombosis of superior vena cava |
| I82211 | Chronic embolism and thrombosis of superior vena cava |
| I8222 | Embolism and thrombosis of inferior vena cava |
| I82220 | Acute embolism and thrombosis of inferior vena cava |
| I82221 | Chronic embolism and thrombosis of inferior vena cava |
| I8229 | Embolism and thrombosis of other thoracic veins |
| I82290 | Acute embolism and thrombosis of other thoracic veins |
| I82291 | Chronic embolism and thrombosis of other thoracic veins |
| I823 | Embolism and thrombosis of renal vein |
| I824 | Acute embolism and thrombosis of deep veins of lower extremity |
| I8240 | Acute embolism and thrombosis of unspecified deep veins of lower extremity |
| I82401 | Acute embolism and thrombosis of unspecified deep veins of right lower extremity |
| I82402 | Acute embolism and thrombosis of unspecified deep veins of left lower extremity |
| I82403 | Acute embolism and thrombosis of unspecified deep veins of lower extremity, bilateral |
| I82409 | Acute embolism and thrombosis of unspecified deep veins of unspecified lower extremity |
| I8241 | Acute embolism and thrombosis of femoral vein |
| I82411 | Acute embolism and thrombosis of right femoral vein |
| I82412 | Acute embolism and thrombosis of left femoral vein |
| I82413 | Acute embolism and thrombosis of femoral vein, bilateral |
| I82419 | Acute embolism and thrombosis of unspecified femoral vein |
| I8242 | Acute embolism and thrombosis of iliac vein |
| I82421 | Acute embolism and thrombosis of right iliac vein |
| I82422 | Acute embolism and thrombosis of left iliac vein |
| I82423 | Acute embolism and thrombosis of iliac vein, bilateral |
| I82429 | Acute embolism and thrombosis of unspecified iliac vein |
| I8243 | Acute embolism and thrombosis of popliteal vein |
| I82431 | Acute embolism and thrombosis of right popliteal vein |
| I82432 | Acute embolism and thrombosis of left popliteal vein |
| I82433 | Acute embolism and thrombosis of popliteal vein, bilateral |
| I82439 | Acute embolism and thrombosis of unspecified popliteal vein |
| I8244 | Acute embolism and thrombosis of tibial vein |
| I82441 | Acute embolism and thrombosis of right tibial vein |
| I82442 | Acute embolism and thrombosis of left tibial vein |
| I82443 | Acute embolism and thrombosis of tibial vein, bilateral |
| I82449 | Acute embolism and thrombosis of unspecified tibial vein |
| I8249 | Acute embolism and thrombosis of other specified deep vein of lower extremity |
| I82491 | Acute embolism and thrombosis of other specified deep vein of right lower extremity |
| I82492 | Acute embolism and thrombosis of other specified deep vein of left lower extremity |
| I82493 | Acute embolism and thrombosis of other specified deep vein of lower extremity, bilateral |
| I82499 | Acute embolism and thrombosis of other specified deep vein of unspecified lower extremity |
| I824Y | Acute embolism and thrombosis of unspecified deep veins of proximal lower extremity |
| I824Y1 | Acute embolism and thrombosis of unspecified deep veins of right proximal lower extremity |
| I824Y2 | Acute embolism and thrombosis of unspecified deep veins of left proximal lower extremity |
| I824Y3 | Acute embolism and thrombosis of unspecified deep veins of proximal lower extremity, bilateral |
| I824Y9 | Acute embolism and thrombosis of unspecified deep veins of unspecified proximal lower extremity |
| I824Z | Acute embolism and thrombosis of unspecified deep veins of distal lower extremity |
| I824Z1 | Acute embolism and thrombosis of unspecified deep veins of right distal lower extremity |
| I824Z2 | Acute embolism and thrombosis of unspecified deep veins of left distal lower extremity |
| I824Z3 | Acute embolism and thrombosis of unspecified deep veins of distal lower extremity, bilateral |
| I824Z9 | Acute embolism and thrombosis of unspecified deep veins of unspecified distal lower extremity |
| I825 | Chronic embolism and thrombosis of deep veins of lower extremity |
| I8250 | Chronic embolism and thrombosis of unspecified deep veins of lower extremity |
| I82501 | Chronic embolism and thrombosis of unspecified deep veins of right lower extremity |
| I82502 | Chronic embolism and thrombosis of unspecified deep veins of left lower extremity |
| I82503 | Chronic embolism and thrombosis of unspecified deep veins of lower extremity, bilateral |
| I82509 | Chronic embolism and thrombosis of unspecified deep veins of unspecified lower extremity |
| I8251 | Chronic embolism and thrombosis of femoral vein |
| I82511 | Chronic embolism and thrombosis of right femoral vein |
| I82512 | Chronic embolism and thrombosis of left femoral vein |
| I82513 | Chronic embolism and thrombosis of femoral vein, bilateral |
| I82519 | Chronic embolism and thrombosis of unspecified femoral vein |
| I8252 | Chronic embolism and thrombosis of iliac vein |
| I82521 | Chronic embolism and thrombosis of right iliac vein |
| I82522 | Chronic embolism and thrombosis of left iliac vein |
| I82523 | Chronic embolism and thrombosis of iliac vein, bilateral |
| I82529 | Chronic embolism and thrombosis of unspecified iliac vein |
| I8253 | Chronic embolism and thrombosis of popliteal vein |
| I82531 | Chronic embolism and thrombosis of right popliteal vein |
| I82532 | Chronic embolism and thrombosis of left popliteal vein |
| I82533 | Chronic embolism and thrombosis of popliteal vein, bilateral |
| I82539 | Chronic embolism and thrombosis of unspecified popliteal vein |
| I8254 | Chronic embolism and thrombosis of tibial vein |
| I82541 | Chronic embolism and thrombosis of right tibial vein |
| I82542 | Chronic embolism and thrombosis of left tibial vein |
| I82543 | Chronic embolism and thrombosis of tibial vein, bilateral |
| I82549 | Chronic embolism and thrombosis of unspecified tibial vein |
| I8259 | Chronic embolism and thrombosis of other specified deep vein of lower extremity |
| I82591 | Chronic embolism and thrombosis of other specified deep vein of right lower extremity |
| I82592 | Chronic embolism and thrombosis of other specified deep vein of left lower extremity |
| I82593 | Chronic embolism and thrombosis of other specified deep vein of lower extremity, bilateral |
| I82599 | Chronic embolism and thrombosis of other specified deep vein of unspecified lower extremity |
| I825Y | Chronic embolism and thrombosis of unspecified deep veins of proximal lower extremity |
| I825Y1 | Chronic embolism and thrombosis of unspecified deep veins of right proximal lower extremity |
| I825Y2 | Chronic embolism and thrombosis of unspecified deep veins of left proximal lower extremity |
| I825Y3 | Chronic embolism and thrombosis of unspecified deep veins of proximal lower extremity, bilateral |
| I825Y9 | Chronic embolism and thrombosis of unspecified deep veins of unspecified proximal lower extremity |
| I825Z | Chronic embolism and thrombosis of unspecified deep veins of distal lower extremity |
| I825Z1 | Chronic embolism and thrombosis of unspecified deep veins of right distal lower extremity |
| I825Z2 | Chronic embolism and thrombosis of unspecified deep veins of left distal lower extremity |
| I825Z3 | Chronic embolism and thrombosis of unspecified deep veins of distal lower extremity, bilateral |
| I825Z9 | Chronic embolism and thrombosis of unspecified deep veins of unspecified distal lower extremity |
| I826 | Acute embolism and thrombosis of veins of upper extremity |
| I8260 | Acute embolism and thrombosis of unspecified veins of upper extremity |
| I82601 | Acute embolism and thrombosis of unspecified veins of right upper extremity |
| I82602 | Acute embolism and thrombosis of unspecified veins of left upper extremity |
| I82603 | Acute embolism and thrombosis of unspecified veins of upper extremity, bilateral |
| I82609 | Acute embolism and thrombosis of unspecified veins of unspecified upper extremity |
| I8261 | Acute embolism and thrombosis of superficial veins of upper extremity |
| I82611 | Acute embolism and thrombosis of superficial veins of right upper extremity |
| I82612 | Acute embolism and thrombosis of superficial veins of left upper extremity |
| I82613 | Acute embolism and thrombosis of superficial veins of upper extremity, bilateral |
| I82619 | Acute embolism and thrombosis of superficial veins of unspecified upper extremity |
| I8262 | Acute embolism and thrombosis of deep veins of upper extremity |
| I82621 | Acute embolism and thrombosis of deep veins of right upper extremity |
| I82622 | Acute embolism and thrombosis of deep veins of left upper extremity |
| I82623 | Acute embolism and thrombosis of deep veins of upper extremity, bilateral |
| I82629 | Acute embolism and thrombosis of deep veins of unspecified upper extremity |
| I827 | Chronic embolism and thrombosis of veins of upper extremity |
| I8270 | Chronic embolism and thrombosis of unspecified veins of upper extremity |
| I82701 | Chronic embolism and thrombosis of unspecified veins of right upper extremity |
| I82702 | Chronic embolism and thrombosis of unspecified veins of left upper extremity |
| I82703 | Chronic embolism and thrombosis of unspecified veins of upper extremity, bilateral |
| I82709 | Chronic embolism and thrombosis of unspecified veins of unspecified upper extremity |
| I8271 | Chronic embolism and thrombosis of superficial veins of upper extremity |
| I82711 | Chronic embolism and thrombosis of superficial veins of right upper extremity |
| I82712 | Chronic embolism and thrombosis of superficial veins of left upper extremity |
| I82713 | Chronic embolism and thrombosis of superficial veins of upper extremity, bilateral |
| I82719 | Chronic embolism and thrombosis of superficial veins of unspecified upper extremity |
| I8272 | Chronic embolism and thrombosis of deep veins of upper extremity |
| I82721 | Chronic embolism and thrombosis of deep veins of right upper extremity |
| I82722 | Chronic embolism and thrombosis of deep veins of left upper extremity |
| I82723 | Chronic embolism and thrombosis of deep veins of upper extremity, bilateral |
| I82729 | Chronic embolism and thrombosis of deep veins of unspecified upper extremity |
| I82A | Embolism and thrombosis of axillary vein |
| I82A1 | Acute embolism and thrombosis of axillary vein |
| I82A11 | Acute embolism and thrombosis of right axillary vein |
| I82A12 | Acute embolism and thrombosis of left axillary vein |
| I82A13 | Acute embolism and thrombosis of axillary vein, bilateral |
| I82A19 | Acute embolism and thrombosis of unspecified axillary vein |
| I82A2 | Chronic embolism and thrombosis of axillary vein |
| I82A21 | Chronic embolism and thrombosis of right axillary vein |
| I82A22 | Chronic embolism and thrombosis of left axillary vein |
| I82A23 | Chronic embolism and thrombosis of axillary vein, bilateral |
| I82A29 | Chronic embolism and thrombosis of unspecified axillary vein |
| I82B | Embolism and thrombosis of subclavian vein |
| I82B1 | Acute embolism and thrombosis of subclavian vein |
| I82B11 | Acute embolism and thrombosis of right subclavian vein |
| I82B12 | Acute embolism and thrombosis of left subclavian vein |
| I82B13 | Acute embolism and thrombosis of subclavian vein, bilateral |
| I82B19 | Acute embolism and thrombosis of unspecified subclavian vein |
| I82B2 | Chronic embolism and thrombosis of subclavian vein |
| I82B21 | Chronic embolism and thrombosis of right subclavian vein |
| I82B22 | Chronic embolism and thrombosis of left subclavian vein |
| I82B23 | Chronic embolism and thrombosis of subclavian vein, bilateral |
| I82B29 | Chronic embolism and thrombosis of unspecified subclavian vein |
| I82C | Embolism and thrombosis of internal jugular vein |
| I82C1 | Acute embolism and thrombosis of internal jugular vein |
| I82C11 | Acute embolism and thrombosis of right internal jugular vein |
| I82C12 | Acute embolism and thrombosis of left internal jugular vein |
| I82C13 | Acute embolism and thrombosis of internal jugular vein, bilateral |
| I82C19 | Acute embolism and thrombosis of unspecified internal jugular vein |
| I82C2 | Chronic embolism and thrombosis of internal jugular vein |
| I82C21 | Chronic embolism and thrombosis of right internal jugular vein |
| I82C22 | Chronic embolism and thrombosis of left internal jugular vein |
| I82C23 | Chronic embolism and thrombosis of internal jugular vein, bilateral |
| I82C29 | Chronic embolism and thrombosis of unspecified internal jugular vein |
| I828 | Embolism and thrombosis of other specified veins |
| I8281 | Embolism and thrombosis of superficial veins of lower extremities |
| I82811 | Embolism and thrombosis of superficial veins of right lower extremities |
| I82812 | Embolism and thrombosis of superficial veins of left lower extremities |
| I82813 | Embolism and thrombosis of superficial veins of lower extremities, bilateral |
| I82819 | Embolism and thrombosis of superficial veins of unspecified lower extremities |
| I8289 | Embolism and thrombosis of other specified veins |
| I82890 | Acute embolism and thrombosis of other specified veins |
| I82891 | Chronic embolism and thrombosis of other specified veins |
| I829 | Embolism and thrombosis of unspecified vein |
| I8290 | Acute embolism and thrombosis of unspecified vein |
| I8291 | Chronic embolism and thrombosis of unspecified vein |
| I870 | Postthrombotic syndrome |
| I8700 | Postthrombotic syndrome without complications |
| I87001 | Postthrombotic syndrome without complications of right lower extremity |
| I87002 | Postthrombotic syndrome without complications of left lower extremity |
| I87003 | Postthrombotic syndrome without complications of bilateral lower extremity |
| I87009 | Postthrombotic syndrome without complications of unspecified extremity |
| I8701 | Postthrombotic syndrome with ulcer |
| I87011 | Postthrombotic syndrome with ulcer of right lower extremity |
| I87012 | Postthrombotic syndrome with ulcer of left lower extremity |
| I87013 | Postthrombotic syndrome with ulcer of bilateral lower extremity |
| I87019 | Postthrombotic syndrome with ulcer of unspecified lower extremity |
| I8702 | Postthrombotic syndrome with inflammation |
| I87021 | Postthrombotic syndrome with inflammation of right lower extremity |
| I87022 | Postthrombotic syndrome with inflammation of left lower extremity |
| I87023 | Postthrombotic syndrome with inflammation of bilateral lower extremity |
| I87029 | Postthrombotic syndrome with inflammation of unspecified lower extremity |
| I8703 | Postthrombotic syndrome with ulcer and inflammation |
| I87031 | Postthrombotic syndrome with ulcer and inflammation of right lower extremity |
| I87032 | Postthrombotic syndrome with ulcer and inflammation of left lower extremity |
| I87033 | Postthrombotic syndrome with ulcer and inflammation of bilateral lower extremity |
| I87039 | Postthrombotic syndrome with ulcer and inflammation of unspecified lower extremity |
| I8709 | Postthrombotic syndrome with other complications |
| I87091 | Postthrombotic syndrome with other complications of right lower extremity |
| I87092 | Postthrombotic syndrome with other complications of left lower extremity |
| I87093 | Postthrombotic syndrome with other complications of bilateral lower extremity |
| I87099 | Postthrombotic syndrome with other complications of unspecified lower extremity |
| O2230 | Deep phlebothrombosis in pregnancy, unspecified trimester |
| O2231 | Deep phlebothrombosis in pregnancy, first trimester |
| O2232 | Deep phlebothrombosis in pregnancy, second trimester |
| O2233 | Deep phlebothrombosis in pregnancy, third trimester |
| O2250 | Cerebral venous thrombosis in pregnancy, unspecified trimester |
| O2251 | Cerebral venous thrombosis in pregnancy, first trimester |
| O2252 | Cerebral venous thrombosis in pregnancy, second trimester |
| O2253 | Cerebral venous thrombosis in pregnancy, third trimester |
| O2291 | Venous complication in pregnancy, unspecified, first trimester |
| O2292 | Venous complication in pregnancy, unspecified, first trimester |
| O2293 | Venous complication in pregnancy, unspecified, first trimester |
| O871 | Deep phlebothrombosis in the puerperium |
| O873 | Cerebral venous thrombosis in the puerperium |
| O879 | Venous complication in the puerperium, unspecified |
| O2290 | Venous complication in pregnancy, unspecified, unspecified trimester |
| Z7901 | Long-term (current) use of anticoagulants |
| Z7902 | Long-term (current) use of antithrombotics/antiplatelets |
| Z86718 | Personal history of other venous thrombosis and embolism |
| Z8672 | Personal history of thrombophlebitis |
| Z8679 | Personal history of other diseases of the circulatory system |
Pulmonary embolism—related ICD-9 codes, CPT codes, and ICD-10 codes
|
ICD-10 codes |
Definition |
|---|---|
| I26 | PE |
| I260 | PE with acute cor pulmonale |
| I2601 | Septic PE with acute cor pulmonale |
| I2602 | Saddle embolus of pulmonary artery with acute cor pulmonale |
| I2609 | Other PE with acute cor pulmonale |
| I269 | PE without acute cor pulmonale |
| I2690 | Septic PE without acute cor pulmonale |
| I2692 | Saddle embolus of pulmonary artery without acute cor pulmonale |
| I2699 | Other PE without acute cor pulmonale |
| I82890 | Acute embolism and thrombosis of other specified veins |
| I8291 | Chronic embolism an thrombosis of unspecified vein |
| O032 | Embolism after incomplete spontaneous abortion |
| O037 | Embolism after complete or unspecified spontaneous abortion |
| O047 | Embolism after (induced) termination of pregnancy |
| O072 | Embolism after failed attempted termination of pregnancy |
| O082 | Embolism after ectopic and molar pregnancy |
| O88 | Obstetric embolism |
| O882 | Obstetric thromboembolism |
| O8821 | Thromboembolism in pregnancy |
| O88211 | Thromboembolism in pregnancy, first trimester |
| O88212 | Thromboembolism in pregnancy, second trimester |
| O88213 | Thromboembolism in pregnancy, third trimester |
| O88219 | Thromboembolism in pregnancy, unspecified trimester |
| O8822 | Thromboembolism in childbirth |
| O8823 | Thromboembolism in the puerperium |
| O883 | Obstetric pyemic and septic embolism |
| O8831 | Pyemic and septic embolism in pregnancy |
| O88311 | Pyemic and septic embolism in pregnancy, first trimester |
| O88312 | Pyemic and septic embolism in pregnancy, second trimester |
| O88313 | Pyemic and septic embolism in pregnancy, third trimester |
| O88319 | Pyemic and septic embolism in pregnancy, unspecified trimester |
| O8832 | Pyemic and septic embolism in childbirth |
| O8833 | Pyemic and septic embolism in the puerperium |
| O888 | Other obstetric embolism |
| O8881 | Other embolism in pregnancy |
| O88811 | Other embolism in pregnancy, first trimester |
| O88812 | Other embolism in pregnancy, second trimester |
| O88813 | Other embolism in pregnancy, third trimester |
| O88819 | Other embolism in pregnancy, unspecified trimester |
| O8882 | Other embolism in childbirth |
| O8883 | Other embolism in the puerperium |
| T800XXA | Air embolism after infusion, transfusion, and therapeutic injection, initial encounter |
| T81718A | Complication of other artery after a procedure, not elsewhere classified, initial encounter |
| T8172XA | Complication of vein after a procedure, not elsewhere classified, initial encounter |
| T82817A | Embolism of cardiac prosthetic devices, implants, and grafts, initial encounter |
| T82818A | Embolismof vascular prosthetic devices, implants, and grafts, initial |
| Z7901 | Long-term (current) use of anticoagulants |
| Z7902 | Long-term (current) use of antithrombotics/antiplatelets |
| Z86711 | Personal history of PE |
| Z86718 | Personal history of other venous thrombosis and embolism |
| Z8679 | Personal history of other diseases of the circulatory system |
Appendix B
Footnotes
Disclosures
This project was funded by CDC funding: DD14-1407. Dr Bratzler would like to disclose a consultancy for CDC and Sanofi Pasteur. Dr Raskob would like to disclose a consultancy and honoraria for Bayer Healthcare, BMS, Boehringer Ingelheim, Daiichi Sankyo, Janssen Pharmaceuticals, Pfizer, and ISIS Pharmaceuticals. Dr Wendelboe would like to disclose an honoraria from Bristol-Myers Squibb. None of the other authors have any disclosures.
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