Frequency and Costs of Hospital Transfers for Ambulatory Sensitive Conditions

Abstract

Objectives

Nursing home (NH) patients are frequently transferred to emergency departments (EDs) and/or hospitalized in situations where transfer might have been avoided. This study describes the frequency of NH transfers for ambulatory care sensitive conditions (ACSC) and estimates associated expenditures.

Study Design

Retrospective cohort study of 62,379 NH patients with Medicare coverage receiving care in South Carolina between 2007 and 2009.

Methods

Subjects were analyzed to determine the frequency acute ED or hospital care for conditions. Comparison is made to similar patients transferred for acute treatment of non-ACSCs. Generalized linear models were used to estimate the costs attributable to treating ACSCs.

Results

20,867 NH subjects were transferred from NHs to acute care facilities, and 85.3% of subjects had at least one episode of care for an ACSC. An average of 13,317 subjects were transferred for an average of 17,060 episodes of ED or hospital care per year between 2007 and 2009. More ACSC patients transferred to EDs were subsequently admitted to the hospital (50.4% vs. 25%, p<0.0001). In adjusted analyses, mean ED costs/episode of care ($401 vs. $294, p<0.0001) were higher, but mean hospitalization costs/episode of care were lower ($8,356 vs. $10,226, p<0.0001) for ACSC patients compared to non-ACSC patients.

Conclusion

A significant proportion of Medicare NH patients are treated acutely for ACSCs which are associated with higher healthcare utilization and costs. Better access to on-site evaluation might enable significant cost savings and reduce morbidity in this population.

Introduction

Millions of Americans receive important, but costly long-term and rehabilitative care in U.S. nursing homes (NHs) each year. Approximately 1.8 million Americans live in U.S. NHs or other skilled nursing facilities, and this number is expected to double in the next 40 years.¹ In addition, up to 4.9 million Medicare recipients receive rehabilitative care in U.S. NHs after acute hospitalization each year.² Medicare, the largest payer for rehabilitation care, spent an estimated $288 million for post-acute rehabilitation and hospice care in 2007.² In South Carolina, there are approximately 16,000 residents living in over 170 NH facilities.³

Nursing home patients are frequently transferred to acute hospital emergency departments (EDs) and subsequently hospitalized.⁴ Hospitalization frequently results in iatrogenic complications and declining health trajectories among elderly patients.⁵ In a recent study, nearly one-fourth of long-term NH residents experienced at least one ED visit in 6 months, and over 60% of ED visits resulted in hospitalization.⁶ Overall, reported annual hospital admission rates for long-term care NH patients range from 9–59%.⁷ Similarly, 23.5% of Medicare patients discharged to skilled nursing facilities are readmitted to acute hospitals within 30 days resulting in an estimated $4.3 billion in excess costs.⁸

An extensive and varied literature exists describing factors associated with NH to ED transfers and hospitalizations.^9–12 Identified predictors include socio-demographic factors such as male gender and increasing age; medical conditions including congestive heart failure, chronic respiratory disease, and dementia; provider-specific factors related to the availability of nurses, physicians, and nurse practitioners; and regulatory factors such as reimbursement rates and bed-hold policies.⁷ When surveyed, providers have indicated several factors that contribute to over-hospitalization.¹³ Some of these include patient and family preferences, lack knowledge on the part of patients and families regarding end-of-life care options such as hospice care, lack of familiarity with patients by covering providers, and lack of timely (<4 hours) access to physician or NP evaluation. Acknowledgement of concern for medico-legal liability is largely absent from the literature, but this may still be a factor in decisions to hospitalize.

Many patients, providers, and policymakers feel that a significant proportion of NH to hospital transfers are potentially avoidable. Indeed, the preventability of such episodes of care has been the subject of much study and debate, but there is no gold standard for determining preventability.^14–17 In one systematic review, low quality inpatient care was associated with a 55% increase in risk for early hospital readmission.¹⁴ However, estimates of hospitalization preventability range from 9–48%.¹⁵ Within this context, it is appealing to analyze a set of diseases for which improvements in care might prevent hospitalization.¹⁸ According the Agency for Healthcare Research and Quality (AHRQ), “Hospitalization for an ambulatory care sensitive condition (ACSC) is considered to be a measure of access to appropriate primary health care. While not all admissions for these conditions are avoidable, it is assumed that appropriate ambulatory care could prevent the onset of this type of illness or condition, control an acute episodic illness or condition, or manage a chronic disease or condition.”¹⁹ For example, with early evaluation, a patient with cellulitis might receive oral antibiotics that could avoid hospitalization for intravenous antibiotics. Similarly, a patient with chronic heart failure receiving early dietary modification and diuretic therapy might avoid hospitalization for volume overload and pulmonary edema.

Thus ACSC analysis represents a useful method for identifying potentially avoidable acute care utilization based on the assumption that facilities with disproportionately high rates have problems with timely access to appropriate primary care.^20–22 Several reports indicate that avoidable hospitalizations for ambulatory care-sensitive conditions are common and costly.^23–25 Carter and colleagues examined an elderly Massachusetts cohort and found that 20.3% of ED visits among NH residents were for ACSCs, and NH residents had a relative risk ratio for hospital admission of 2.23 (95% CI 1.744, 2.855) compared to community dwelling patients. In addition, acute care costs for ACSCs in NH patients are quite high, estimated at 23% of the $971 million spent on NH residents in New York state.²⁶

The current literature on ACSC in NH patients has several limitations. Most studies have analyzed ED visit rates, or hospitalizations, but not both.^6,25,27 Also, relatively few studies have analyzed costs of care for ACSC among nursing home patients.²⁶ Finally, more robust studies are needed that more accurately analyze actual costs attributable to ACSC in NH patients. Such cost figures can be used to estimate cost savings based on the projected or actual effect sizes of different interventions designed to reduce nursing home transfers. The purpose of this project was to determine the frequency of ED visits and hospitalizations for ACSC among NH patients and to determine Medicare expenditures for these patients.

Methods

Study population

We constructed a statewide cohort of Medicare insured patients receiving care in South Carolina nursing homes during calendar years 2007–2009. Data sources included Medicare Provider Analysis and Review (MedPar), Medicare Outpatient Carrier, and Medicare Annual Beneficiary Summary files from the Centers for Medicare and Medicaid Services (CMS). Datasets were linked using a unique patient identifier code. Selection criteria included: 1) Age ≥ 18 years 2) Enrolled in Medicare 3) Billed for an acute hospitalization, ED visit, long-term nursing home stay, or inpatient rehabilitation in a South Carolina NH. Subjects were included in the present cohort if they had a NH admission and discharge date within the study timeframe. We categorized subjects as having had acute ED visits or hospitalizations if they had encounters that fell during the period of a NH stay. Episodes of acute care were further categorized as ED only visits, ED-hospitalization visits, or hospitalization only visits. This study was reviewed and approved by our local institutional review board. All analyses were conducted using SAS version 9.3 (SAS Institute, Carey, NC).

Ambulatory care sensitive conditions

Ambulatory care sensitive conditions have been used in a number of prior health services research studies examining access to primary care services including studies of nursing home and skilled care populations.^23,28 For this study, we used a modification of the coding scheme for ACSC recommended by the AHRQ.²⁹ Subjects were categorized as having been treated for ACSC diagnoses or not. Ambulatory care sensitive conditions and relevant ICD-9 codes are shown in Table 2. Given the age range of our population, we excluded congenital syphilis (ICD-9 090), hemophilus meningitis age 1–5 only (ICD-9 320.2), convulsions age < 5 years (ICD-9 780.3), and failure to thrive age < 1 year (ICD-9 783.4). We further categorized ACSCs as ‘acute and/or preventable’ versus ‘chronic’. Finally, given the nature of our research question, and in order to better characterize total hospital costs attributable to ACSC, we examined subjects with ACSCs as either a primary or secondary diagnosis.

Table 2.

Ambulatory Care Condition Frequencies.

Acute Preventable Conditions
	N subjects/year	N episodes of care/year
Iron Deficiency Anemia [ICD-9 280.1,280.8,280.9]	128	133
Bacterial Pneumonia [ICD-9 481,482.2,482.3,482.9,483,485,486]	428	465
Cellulitis [ICD-9 681,682,683,686]	334	361
Convulsions [ICD-9 780.3]	188	218
Dehydration / Volume Depletion [ICD-9 276.5]	1159	1301
Gastroenteritis [ICD-9 558.9]	56	57
Hypoglycemia [ICD-9 251.2]	32	34
Kidney/Urinary Infection [ICD-9 590.0,599.0,599.9]	2118	2614
Severe Ear, Nose, & Throat Infections [ICD-9 382,462,463,465,472.1]	37	38
Other Conditions*	200	212
Total (subjects / year)	4680	5433
Chronic Conditions
Angina [ICD-9 411.1,411.8,413]	73	77
Asthma [ICD-9 493]	217	258
Chronic Obstructive Pulmonary Disease [ICD-9 466.0,491,492,494,496]	1167	1517
Congestive Heart Failure [ICD-9 402.01,402.11,402.91,428,518.4]	2020	2772
Diabetes [ICD-9 250.0–250.3,250.8–250.9]	1927	2811
Grand Mal & Other Epileptic Conditions [ICD-9 345]	230	294
Hypertension [ICD-9 401.0,401.9,402.00,402.10,402.90]	3001	3895
Tuberculosis (Non-Pulmonary) [ICD-9 012-018]]	2	3
Total	8637	11627
Grand Total	13317	17060

^*Other conditions included: Dental Conditions [ICD-9 521–523,525,528], Nutritional Deficiencies [ICD-9 260–262,268.0,268.1], Cancer of the Cervix [ICD-9 180.0–180.1,180.8–180.9], and Pelvic Inflammatory Disease [ICD-9 614] Excluded conditions were: congenital syphilis [ICD-9 090], hemophilus meningitis age 1–5 only [ICD-9 320.2], convulsions age < 5 years [ICD-9 780.3], and failure to thrive age < 1 year [ICD-9 783.4]

Outcome measures

The primary outcome measures for this study were measures of acute healthcare utilization and associated hospital costs for patients treated for ACSC compared to those treated acutely for non-ACSC. We determined the number of subjects treated and the number of episodes of care per year for each ACSC. We further determined the mean number ED visits and hospitalizations per subject and the total numbers of visits overall. The primary cost outcome for adjusted analyses was mean Medicare expenditures for ED visits and/or hospitalization.

Covariates

In addition to treatment for ACSC, we also examined several other covariates. Age and length of NH stay were analyzed as continuous variables. Gender (male/female) and race (white/other) were analyzed as categorical variables. Baseline comorbidity was analyzed using chronic condition flags present in the Medicare Annual Beneficiary Summary file, provided the date of first diagnosis occurred prior to the index NH stay. These included: acute myocardial infarction/ischemic heart disease; Alzheimer’s disease/dementia; atrial fibrillation; cataract; chronic kidney disease; chronic obstructive pulmonary disease; congestive heart failure; diabetes mellitus; depression; osteoporosis; stroke; and cancer.

Statistical Analysis

Descriptive statistics (means, medians, and proportions) of demographic variables, length of hospital stay, chronic conditions present in beneficiary summary file prior to the index episode and acute care utilization (e.g. Hospital readmission, ICU admission, etc.) were calculated by ACSC status (with versus without ACSC). We also calculated the frequency of episodes of care per year stratified by chronic and acute preventable conditions. In order to determine costs attributable to the care of ACSC adjusted for relevant covariates described above, we fitted a generalized linear model estimated via generalized estimating equations and a gamma distribution with a log link. This approach enabled us to estimate costs with robust standard error estimates for making inference regarding expenditures. Adjusted mean costs are reported in U.S. dollars calculated from the model predicted costs with all dollar values adjusted using the consumer price index to 2009 dollars.

Results

Subject Characteristics

This cohort represented a 100% sample of Medicare recipients treated in South Carolina nursing homes during calendar years 2007–2009. Table 1 describes characteristics of NH subjects treated in ED or hospitalized for ACSC compared to those treated for non-ACSC. Overall, 17,794 of 20,867 transferred patients (85.3%) were treated for at least one ACSC condition as a primary or secondary diagnosis during an episode of acute care. Mean age, the proportion of female subjects, and the proportion of non-white subjects were similar between groups. Nursing home length of stay and the proportion of long-stay (i.e. > 30 days) NH patients were higher among subjects in the ACSC group. Both groups had significant numbers of subjects with pre-existing chronic diseases, but chronic ACSC including congestive heart failure (69.2% vs. 54.7%), chronic obstructive pulmonary disease (47.7% vs. 37.6%), diabetes (56.5% vs. 39.9%) were higher in the ACSC group compared to the non-ACSC group.

Table 1.

Subject Characteristics (N= 20,867 subjects)

	ACSC Diagnoses*	No ACSC Diagnoses	p-value
N subjects	17,794 (85.3%)	3,073 (14.7%)
Age (mean, SD)	80.7 ± 10.4	80.2 ± 11.2	0.0245
Female (%)	64.0	59.6	<0.0001
Race			0.0108
White (%)	75.0	77.1
Other (%)	25.0	22.9
NH Length of Stay (median)	50	72	<0.0001
Short Stay (%)	25.0	34.4	<0.0001
Long Stay (%)	75.0	65.6
Chronic Conditions**
AMI/Ischemic heart disease	13027 (73.2%)	1941 (63.2%)	<0.0001
Alzheimer’s disease/Dementia	10332 (58.1%)	1671 (54.4%)	0.0001
Atrial Fibrillation	6198 (34.8%)	925 (30.1%)	<0.0001
Cataract	14309 (80.4%)	2405 (78.3%)	0.0283
Chronic Kidney Disease	10301 (57.9%)	1471 (47.9%)	<0.0001
Chronic Obstructive Pulmonary Disease	8491 (47.7%)	1155 (37.6%)	<0.0001
Congestive Heart Failure	12317 (69.2%)	1682 (54.7%)	<0.0001
Diabetes Mellitus	10056 (56.5%)	1225 (39.9%)	<0.0001
Depression	9599 (54.0%)	1522 (49.5%)	<0.0001
Osteoporosis	7656 (43.0%)	1293 (42.1%)	0.3373
Stroke	7923 (44.5%)	1192 (38.8%)	<0.0001
Cancer	3090 (17.4%)	584 (19.0%)	0.0060

NH=Nursing home, AMI=Acute myocardial infarction

^*One or more ACSC condition listed among discharge diagnoses for an index episode of care. Not all episodes of care for each patient included ACSC diagnoses.

^**Chronic conditions present in beneficiary summary file prior to the index episode of care

Ambulatory Care Sensitive Conditions

Table 2 describes the types of treated ACSC grouped according to acute and preventable conditions or chronic conditions. Over the 3 year study period, 4,680 patients were treated for a total of 5,433 episodes of acute and preventable conditions. Dehydration/volume depletion and kidney/urinary tract infections were the most frequent acute ACSC treated. More patients were seen for chronic ACSC than acute/preventable with 8,637 subjects treated for 11,627 episodes of care. Hypertension, diabetes mellitus, and congestive heart failure were the most frequent chronic conditions treated.

Healthcare Utilization

Table 3 displays several domains of acute ED and hospital utilization in ACSC subjects compared to non-ACSC subjects. During the 3 year study period, NH patients experienced 27,382 episodes of care for ACSC compared to only 7,200 episodes of care without ACSC. A significantly higher proportion of NH patients seen in the ED with ACSC diagnoses were subsequently admitted to the hospital (50.4% vs. 24%, p<0.0001). Nursing home to hospital transfers representing hospital readmissions were not significantly different between the ACSC and non-ACSC condition groups (15.1% vs. 16.0%, p=0.26). ICU admission was almost twice as common in the ACSC condition group (10.2% vs. 5.6%, p<0.0001). Patients treated for ACSC diagnoses had higher mean numbers of ED visits per subject (1.5 vs. 1.2, p< 0.0001) and hospitalizations per subject (1.3 vs. 1.1, p<0.0001) than did non-ACSC subjects with the total number of ED visits and hospital visits occurring in similar proportions.

Table 3.

Acute Care Utilization among Transfers from Nursing Homes (N=34,582 episodes of care)

	ACSC Diagnoses	No ACSC Diagnoses	p-value
Type of Transfer (n)	27382	7200
ED only (%)	10060 (36.7%)	4769 (66.2%)	<0.0001
ED and admission (%)	13790 (50.4%)	1725 (24%)	<0.0001
Admission only (%)	3532 (12.9%%)	706 (9.8%)	<0.0001
Hospital Readmissions* (n, %)	2614 (15.1%)	388 (16.0%)	0.2632
ICU Admission** (n, %)	2792 (10.2%)	406 (5.6%)	<0.0001
Mean number of ED visits/subject	1.5	1.2	<0.0001
Mean number of hospitalizations/subject	1.3	1.1	<0.0001
Total ED visits/year	7950	2165	<0.0001
Total Hospital Admissions/year	5774	810	<0.0001

^*Index hospital admission occurred within 30 days of a previous acute care hospital discharge

^**Index hospital admission included an ICU stay

Attributable Costs

Table 4 highlights estimated costs for ED care and hospitalization among NH subjects transferred for ED care and hospitalization for ACSC compared to non-ACSC after adjustment for demographic factors and comorbid chronic diseases. Adjusted mean ED costs were ~$100 more ($401 vs. $294, p<0.0001) for episodes of ED care for ACSC patients compared to non-ACSC patients. However, adjusted mean hospitalization costs were ~$1,900 less ($8,356 vs. $10,226, p<0.0001) for hospitalizations for ACSC patients compared to non-ACSC patients. Given the markedly higher numbers of ACSC subjects, total annual expenditures for ACSC were significantly higher in each category. Model coefficients are displayed in Table 5.

Table 4.

Estimated Acute Care Costs Attributable to Ambulatory Care Sensitive Conditions^*

	ACSC Diagnoses	No ACSC Diagnoses	p-value
ED costs/episode ($)	401	294	<0.0001
Total ED costs/year ($)	1,344,687	467,362
Inpatient costs/episode ($)	8356	10226	<0.0001
Total inpatient costs/year ($)	48,247544	8,286,469

^*Cost estimates adjusted for patient age, gender, race, chronic comorbid conditions, and ACSC as primary or secondary diagnosis

Table 5.

Regression Model Estimating Adjusted Mean Costs Attributable to Ambulatory Care Sensitive Conditions

	Estimate	95% Confidence Intervals		P Value
Intercept	9.0514	8.9414	9.1613	<.0001
Age	−0.0024	−0.0036	−0.0013	<.0001
Race (White = referent)	0.0519	0.0275	0.0762	<.0001
Gender (Male = referent)	−0.0078	−0.0304	0.0147	0.4957
ACSC (ACSC as principle diagnosis)	0.2250	0.2038	0.2463	<.0001
AMI/Ischemic heart disease	−0.0073	−0.0312	0.0166	0.5512
Alzheimer’s disease/Dementia	0.0639	0.0424	0.0855	<.0001
Cancer	−0.0076	−0.0329	0.0177	0.5571
Cataract	0.0020	−0.0247	0.0287	0.8832
Atrial Fibrillation	−0.0118	−0.0330	0.0094	0.2742
Congestive Heart Failure	−0.0160	−0.0396	0.0075	0.1824
Chronic Obstructive Pulmonary Disease	0.0047	−0.0152	0.0245	0.6446
Chronic Kidney Disease	−0.0169	−0.0370	0.0031	0.0978
Diabetes Mellitus	0.0134	−0.0068	0.0337	0.1930
Depression	0.0021	−0.0190	0.0232	0.8446
Osteoporosis	−0.0069	−0.0290	0.0152	0.5402
Stroke	0.0213	0.0020	0.0405	0.0302
Arthritis	0.0103	−0.0109	0.0315	0.3392
Hip Fracture	0.0217	−0.0005	0.0440	0.0556
Acute Myocardial Infarction	0.2021	0.1546	0.2495	<.0001
Visit Type (ED or Admission)	−3.0359	−3.0572	−3.0146	<.0001
Visit Type*ACSC	−0.5140	−0.5720	−0.4560	<.0001

Discussion

This report represents the first study to analyze ED and acute hospital utilization in a Medicare cohort at the state level while using robust methods for estimating attributable health care costs. Our results confirm that a majority of patients transferred from NH to hospitals for ED care and/or hospitalization are treated for ACSC as a primary or secondary diagnosis. ACSC patients appear to be more likely to get admitted to the hospital from the ED and more likely to be admitted to the ICU, based on bivariate analyses. In fully adjusted regression models, overall utilization and Medicare expenditures are higher for patients transferred from NH to EDs than for patients without ACSC. Total annual costs were significantly higher in ACSC patients compared to non-ACSC patients. This is important because prior studies have suggested that early access to primary and preventive care may obviate or diminish the need for acute care in patients with these conditions. Clearly, most acute care transfers are likely appropriate, especially in instances of critical illness. However, our results suggest that additional measures to improve on-site management of ACSC might prevent avoidable NH to acute care transfers among stable patients and/or decrease the severity of illness among patients destined to require acute care transfers. Both of these phenomena could have favorable effects on healthcare utilization and expenditures.

Previously successful strategies to reduce NH to ED transfers and hospitalizations have focused on improving access to care through innovative payment policies, improving care quality for specific diseases, and increasing referrals for hospice care.^30–32 For example, Casarett and colleagues introduced a simple communication intervention to identify NH patients and families whose care preferences were congruent with palliative approaches to care.³² Patients randomized to this intervention had higher hospice enrollment rates, half as many acute hospitalizations, and fewer days spent in acute hospitals. Kane and colleagues (2004) described the effects of an innovative Medicare payment program that increased the availability of nurse practitioners to NH residents.^30,33 Intervention patients had half as many hospitalizations (2.43/100 patients/month vs. 4.67/100 patients/month, p < 0.001) compared to control patients at other facilities as well as 9% lower hazard for mortality compared to non-intervention patients at the same facilities. The program was estimated to save $103,000 per year per NP.

In terms of clinical management interventions, Loeb and colleagues demonstrated in a cluster-randomized trial that early initiation of a clinical pathway for on-site treatment of pneumonia resulted in a 12% absolute reduction in hospitalizations (95% CI 5%, 18%, p < 0.001) and a trend towards decreased mortality. This intervention was also evaluated to be cost-effective estimated to save $1016 per resident (95% CI $207, $1824). Unfortunately, the innovations described here have not been widely disseminated, and many NH professionals still regard access to timely, well-informed evaluations for acutely ill residents as a significant limitation in most nursing homes.¹³ Many have called for new and effective strategies to reduce NH transfers and hospitalizations given that prior efforts at NH regulation and market-based incentives have had only modest effects on quality metrics.³⁴

Our findings have several implications for healthcare policymakers and intervention developers. CMS, in provisions related to the Accountable Care Act (ACA) has recently encouraged the development of Community-based Care Transitions Programs as well as pilot initiatives specifically focused on reducing avoidable nursing home transfers.^35,36 Section 3025 of the ACA established penalties for hospitals with higher than expected risk adjusted hospital readmission rates for congestive heart failure, one of the ACSC, and COPD will be added to this list in 2014.³⁷ Finally, several bundled care demonstration projects are underway for post-hospital care that aim to improve care transitions for Medicare enrollees.³⁸ All of these endeavors can benefit from reliable estimates of cost attributable to ambulatory care sensitive conditions among NH residents.

In considering potential interventions to reduce acute care transfers, it is plausible to hypothesize that real time video teleconferencing might overcome barriers in access to on-site physician and NP providers in NH settings. This redesign of the delivery system could be easily coupled with decision support similar to successful clinical management pathways for ACS conditions as in prior clinical trials.³¹ Wade and colleagues (2010) reviewed 36 trials utilizing real-time video telehealth interventions in a variety of settings, and the majority of these interventions offered superior or equivalent health outcomes and were deemed cost-saving or cost-neutral.³⁹ Real-time video telehealth has been used successfully in rural settings to increase subspecialty physician access and in the home setting to improve chronic disease management.^39,40 Daly and colleagues (2005) demonstrated the feasibility of establishing real-time videoconferencing in NHs, but no trial to date has assessed the effectiveness of this type of intervention.⁴¹ One barrier to implementation of telehealth and other interventions relates to expected cost outlays and estimating potential cost savings. Our analysis should prove useful to intervention developers in this respect.

This report should be evaluated in light of its limitations. First, our analysis involves a single state, South Carolina, and the observed frequencies and costs of acute care for ACSC might not be generalizable nationally. However, based on 2006–2007 data from the Commonwealth Fund, South Carolina ranked 28^th in the nation in Medicare hospital admissions per 100,000 beneficiaries, near the median national rate.⁴² Second, our dataset did not include information on costs related to ambulance transportation. Grunier and colleagues reported that, in one cohort of long term care patients, over 90% of patients transferred to the ED required ambulance transport.⁶ Thus, our results may underestimate total costs associated with ED and hospital transfers, especially for Medicare patients. We analyzed costs in aggregate without breaking them down into relevant cost centers. Thus we are unable to comment on, for example, the relative contribution of radiographic tests versus laboratory testing or pharmacy costs. Finally, there were baseline differences in the prevalence of several chronic conditions between patients in the ACSC condition group and the non-ACSC condition group. It is possible that difference in severity of illness influenced patients’ clinical conditions and/or provider decision making during episodes of acute illness. Nevertheless, non-ACSC subjects had high levels of chronic disease including heart disease, dementia, chronic kidney disease, depression, stroke, and cancer.

This study has relative strengths as well. We were able to examine a large cohort and outline frequency and attributable costs for the acute care of ACSC in Medicare. Our cost estimates include both emergency department and inpatient costs and represent actual payments received by Medicare rather than examining hospital charges as has been done in previous reports.²⁶

Take-Away Points.

Nursing home patients are frequently transferred to emergency departments or admitted to acute care facilities for ambulatory care sensitive conditions (ACS) in situations where more timely access to on-site primary care services might have diminished the need for transfer.

• 85.3% of transferred patients had at least one ACS diagnosis.

• 50.4% of ACS patients seen in emergency departments were subsequently admitted to the hospital (vs. 25% for patients without ACS, p<0.0001).

• Mean ED costs/episode of care ($401 vs. $294, p<0.0001) were higher for ACS patients, but mean hospitalization costs/episode of care were lower ($8,356 vs. $10,226, p<0.0001).