Noninfectious Hospital Adverse Events Decline After Elimination of Contact Precautions for MRSA and VRE

Abstract

Objective:

Evaluate the impact of discontinuing routine contact precautions (CP) for endemic methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) on hospital adverse events.

Design:

Retrospective, nonrandomized, observational, quasi-experimental study.

Setting:

Academic medical center with single occupancy rooms.

Participants:

Inpatients.

Methods:

We compared hospital reportable adverse events one year before (pre-period) and after (post-period) discontinuation of routine CP for endemic MRSA and VRE. Throughout the pre-period, daily chlorhexidine gluconate bathing was expanded to nearly all inpatients. Chart review was performed to identify which patients/events were associated with CP for MRSA/VRE in the pre-period and which would have meet prior criteria for MRSA/VRE CP, but not isolated in the post-period. Adverse events during the two periods were compared using segmented and mixed-effects Poisson regression models.

Results:

There were 24,732 admissions in the pre-period and 25,536 in the post-period. Noninfectious adverse events (postoperative respiratory failure, hemorrhage/hematoma, thrombosis, wound dehiscence, pressure ulcers, falls/trauma) decreased by 19% (12.3 to 10.0 per 1,000 admissions, p=0.022) from the pre to post period. There was no significant difference in rate of infectious adverse events after CP were discontinued (20.7 to 19.4 per 1,000 admissions, p=0.33). Patients with MRSA/VRE had the largest reduction in noninfectious adverse events after CP were discontinued with a 72% reduction (21.4 to 6.08 per 1,000 MRSA/VRE admissions, p<0.001).

Conclusion:

After discontinuing routine CP for endemic MRSA/VRE, the rate of noninfectious adverse events declined, especially in patients who no longer required isolation. This suggests that elimination of CP may substantially reduce noninfectious adverse events.

Introduction:

Although both the Infectious Diseases Society of America and Society for Healthcare Epidemiology of America still recommend contact precautions (CP) to decrease transmission of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) in acute care hospitals, recent data has called into question if this should remain standard of care.^1–8

Several institutions have eliminated routine CP for MRSA and VRE, and instead, solely employ horizontal infection prevention strategies to decrease spread of resistant organisms, such as improved hand hygiene, and targeted or universal decolonization with products like chlorhexidine gluconate (CHG).^3,6–8 Three studies specifically looking at infectious outcomes of removing routine CP have not shown an increase in infectious complications, such as device associated infections, MRSA acquisitions, MRSA environmental contamination, and healthcare associated infections with MRSA and/or VRE.^6–8 While there has been some data supporting CP in combination with other horizontal strategies, the data on gowns and gloves alone are lacking.^3,9–20

Multiple studies have shown potential patient harms associated with use of CP, including increased preventable adverse events, such as falls, pressure ulcers, medication administration errors, and deep vein thrombosis (DVT).^21–23 CP have also been associated with fewer healthcare provider visits, shorter healthcare provider contact time, and lack of appropriate documentation.^21,24–28 Patients can experience delays in admission from the emergency room, delays in discharge to skilled nursing facilities, and increased hospital length of stay.^21,29–32 Patients also had increased anxiety, increased depression, and lower satisfaction when compared to patients not in isolation.^21,33,34 Although the patient harms data are concerning, newer studies have had conflicting results. Two more recent studies have not found increased adverse events in patients on CP leading to ongoing uncertainty about the impact of CP on hospital adverse events.^35,36

University of California, Los Angeles (UCLA) Health eliminated routine CP for endemic MRSA and VRE in 2014 and published a quasi-experimental study evaluating the impact of removing CP for these organisms on healthcare associated infections with MRSA and VRE.⁶ Endemic was defined as a non-outbreak setting, with stable baseline rates of MRSA (0.43 LabID clinical cultures per 100 admissions) and VRE (0.62 clinical cultures per 100 admissions). The study showed no increase in MRSA or VRE LabID clinical cultures, colonization, or rates of drug resistance, and showed significant savings in healthcare worker time and $643,776 per year on materials.

The purpose of this study is to determine the impact of discontinuing routine CP for endemic MRSA and VRE on infectious and noninfectious adverse events.

Methods:

Hospital Setting:

This study was conducted at Ronald Reagan-UCLA Medical Center (RRUCLA), which is a 540-bed tertiary, academic hospital, with 154 intensive care unit beds, large transplant population, and level 1 trauma center. All rooms are single occupancy and have alcohol-based hand rubs and sinks for hand hygiene. CP rooms are additionally equipped with signage, isolation gowns, and gloves.

Study Design:

We performed a retrospective, nonrandomized, observational, quasi-experimental study comparing infectious and noninfectious adverse events at RRUCLA. The pre-period was from June 1, 2013 to May 31, 2014 and the post-period was from July 1, 2014 to June 30, 2015. Routine CP were discontinued on July 1, 2014 for endemic MRSA and VRE, including infection, colonization, and prior history of MRSA and/or VRE.⁶ CHG bathing was required in ICUs since 2012, except neonatal. Daily 2% CHG bathing was expanded throughout the pre-period to eventually include all patients by May 2014, except neonates and perinatal patients. Compliance with CHG bathing was documented in the medical record and regularly audited. Adverse events data were collected for both periods. The calendar month of June 2014 was excluded from evaluation given that the new isolation policy changes were rolled-out this month and CP was less consistent, making the data from this month less reliable.

Adverse events data were collected retrospectively from 4 sources: Center for Medicare & Medicaid Services’ Hospital Acquired Conditions (HAC), Agency for Healthcare Research and Quality’s Patient Safety Indicators (PSI), National Healthcare Safety Network (NHSN), and the internal UCLA adverse events reporting system.^37–39 Prior to data extraction and analysis, our team reviewed all routinely reported adverse event categories in the databases and selected event types most likely to be impacted by lack of contact with healthcare providers. Adverse events deemed independent of provider contact time were excluded (Table 1). “Noninfectious” adverse events included: falls and trauma, postoperative hemorrhage and/or hematoma, postoperative respiratory failure, wound dehiscence, pressure ulcer, and pulmonary embolism (PE) and/or DVT. “Infectious” adverse events included hospital onset Clostridium difficile (C. difficile) infection, catheter associated urinary tract infection (CAUTI), central line associated blood stream infection (CLABSI), postoperative sepsis, surgical site infection (SSI), and ventilator associated pneumonia (VAP). Table 1 describes the source of each adverse event. If data could be collected from more than one source, the data were aggregated and duplicate events were removed. Adverse events were defined and collected according to standardized definitions provided by each agency prior to the study for regulatory reporting purposes by hospital employees. The date used for inclusion in either the pre- or post-period was the exact event date entered into the database, or if not available, the date of discharge. There were no changes in collection methodology or reporting during the study period.

Table 1.

Sources of the adverse event data.

Outcomes Data	Event Reporting System
	NHSN	HAC	PSI
Infectious Adverse Events	X
- Hospital onset Clostridium difficile infections	X
- Catheter-associated urinary tract infections	X
- Central line associated bloodstream infections	X
- Post operative sepsis			X
- Surgical Site Infections	X
- Ventilator associated events	X
Non-infectious Adverse Events
- Falls and trauma		X
- Pressure ulcers		X	X
- Post operative respiratory failure			X
- Wound dehiscence			X
- Post operative hemorrhage and/or hematoma			X
- Pulmonary emboli and deep vein thrombosis		X	X

NHSN: National Healthcare Safety Network

HAC: Hospital Acquired Conditions

PSI: Patient Safety Indicators

Internal reporting system – checked for all of the above events if not otherwise reported to one of these agencies

Given differences in reporting definitions, all events found in each system were included. If data could be collected from more than one source, data from all sources were included and duplicates of the same event were removed.

Excluded Conditions: Accidental Puncture or Laceration, Air Embolism, Birth Trauma, Blood Incompatibility, Death Rate among Surgical Inpatients with Serious Treatable Complications, Death Rate in Low-Mortality Diagnosis Related Groups, Foreign Object Retained After Surgery, Iatrogenic Pneumothorax, Manifestations of Poor Glycemic Control, Obstetric Trauma Rate, Postoperative Acute Kidney Injury Requiring Dialysis Rate, Transfusion Reaction Rate

This study was exempt by the UCLA Institutional Review Board as nonhuman subjects research given the data was collected for quality improvement purposes prior to this study.

Each adverse event was associated with an isolation type, either “MRSA and/or VRE,” “other isolation” (multi-drug resistant Acinetobacter, carbapenem-resistant Enterobacteriaceae, aminoglycoside resistant Pseudomonas, and C. difficile infection), “combination” (other isolation + MRSA/VRE), and “no isolation.” Additional isolation statuses, including droplet, airborne, or syndromic indications for isolation, were not evaluated in this study. The data regarding isolation status were collected from the electronic health record. In the post-period, patients were not isolated for MRSA/VRE, so they did not have an electronic isolation alert. Instead, investigators applied previous criteria for MRSA/VRE isolation (history of MRSA/VRE alerts in the electronic health record in the previous 5 years, positive MRSA/VRE screening culture or clinical culture in the previous 2 years) to determine who would have previously qualified for isolation. A chart review was performed to collect demographic and hospitalization-specific data for patients with an adverse event.

Statistical Analysis:

Patient characteristics for those who experienced infectious or non-infectious adverse events were summarized pre/post-CP using means for continuous variables and frequencies (%) for categorical variables (Table 2).

Table 2.

Demographics of patients with an adverse event.

	Infectious Adverse Events		Non-Infectious Adverse Events
	Before (n=523)	After (n=505)	Before (n=312)	After (n=260)
Age (years)	52 (SD±22)	54 (SD±21)	56 (SD±20)	57 (SD±18)
Male	45%	49%	63%	59%
Length of Stay (days)	53 (SD±100)	44 (SD±83)	39 (SD±52)	39 (SD±71)
Insurance
Medicare	38%	35%	45%	44%
MediCal	20%	19%	25%	25%
ICU	43%	38%	40%	45%
Transplant	20%	20%	27%	20%
Hospital Primary Team
Medicine	29%	31%	13%	12%
Surgery	60%	58%	82%	83%
Other	11%	10%	4%	5%
Charlson Comorbidity Index	2.8 (SD±2.0)	3.0 (SD±2.1)	2.8 (SD±1.9)	2.9 (SD±2.1)

SD = Standard deviation

MediCal = California Medicaid

We assessed the effect of eliminating CP on adverse events using two approaches. First, we tested for overall differences in adverse event rates pre/post using Poisson regression models by including only a pre/post predictor variable (Table 3/4). We then ran longitudinal Poisson models taking into account monthly trends in adverse event incidence to test for immediate effects of the intervention as well as compute slope differences pre/post CP discontinuation. This was carried out using interrupted time series analysis (segmented regression analysis) as described by Wagner et al.⁴⁰ Specifically, we used Poisson mixed effects models with the outcome as the adverse event of interest and predictor terms for the baseline trend, level change after the intervention, trend change after intervention, and a patient random effect. Rates reported are per 1,000 admissions unless otherwise noted. Statistical summaries (incidence rate ratios, 95% confidence intervals, p-values) and figures from these models are presented in Figures 1/2 and Tables 3/4.

Table 3.

Change in the rate of infectious and noninfectious adverse events after the policy change.

Adverse Event	Rate Before n=24,732 admissions	Rate After n=25,536 admissions	p value	Slope Change	p value
Non-infectious Adverse Events	12.3	10.0	0.02*	0.94 (0.90–0.99)	0.028*
Falls and Trauma	1.1	0.70	0.16	0.90 (0.76–1.06)	0.21
Hemorrhage and/or Hematoma	5.5	4.5	0.12	0.89 (0.83–0.96)	0.004*
Post Operative Respiratory Failure	1.42	1.80	0.28	0.95 (0.83–1.09)	0.48
Wound Dehiscence	0.1	0.2	0.51	0.94 (0.59–1.51)	0.80
Pressure Ulcer	1.2	0.7	0.053	0.96 (0.81–1.14)	0.64
Pulmonary Embolism and/or Deep Vein Thrombosis	3.0	2.2	0.08	1.05 (0.95–1.16)	0.36
Infectious Adverse Events	20.7	19.4	0.33	0.99 (0.95–1.02)	0.43
Hospital Onset C. difficile	6.5	6.5	0.96	1.02 (0.96–1.08)	0.58
Catheter Associated UTI	4.0	3.4	0.30	0.95 (0.88–1.03)	0.23
Central Line Associated Blood Stream Infection	4.4	4.6	0.78	1.02 (0.94–1.10)	0.68
Post Operative Sepsis	0.4	0.6	0.38	1.15 (0.93–1.43)	0.20
Surgical Site Infection	5.2	4.0	0.03*	0.89 (0.83–0.96)	0.002*
Ventilator Associated Pneumonia	0.2	0.4	0.17	1.34 (0.99–1.83)	0.06

^*Statistically significant

UTI = urinary tract infection

Rates – per 1,000 admissions

Slope change = incidence rate ratio with 95% confidence interval

Table 4.

Change in the rate of noninfectious adverse events after the policy change based on isolation status.

Isolation Status	Rate Before n=24,732 admissions++	Rate After n=25,536 admissions++	Percent Decrease	p value	Slope Change	p value
No Isolation	9.9	9.9	0%	0.99	0.94 (0.89–0.99)	0.03*
MRSA and/or VRE	21.4	6.08	72%	<0.001*	0.84 (0.70–1.00)	0.49*

^*Statistically significant

Rates – Noninfectious adverse events per 1,000 admissions

Slope change = incidence rate ratio with 95% confidence interval

⁺⁺MRSA/VRE = 12% of admissions; non-MRSA/VRE = 88% of admissions. These denominators were used to calculate the respective rates.

Figure 1.

Monthly rates of infectious and noninfectious adverse events before and after contact precautions were discontinued for MRSA and/or VRE.

CP = contact precautions

Pre – with contact precautions for both MRSA and VRE

Post – no contact precautions for MRSA or VRE

Trend lines – slopes of the monthly incidence rate ratios for pre and post, as well as change point for immediate effect

Figure 2.

Comparison of isolation status and rate of noninfectious adverse events.

CP = contact precautions

Pre – with contact precautions for both MRSA and VRE

Post – no contact precautions for MRSA or VRE

Trend lines – slopes of the monthly incidence rate ratios for pre and post, as well as change point for immediate effect

MRSA/VRE = 12% of admissions

Non-MRSA/VRE = 88% of admissions.

Denominators – Figure A – based on admissions with no MRSA; Figure B – based on rate of admission with MRSA/VRE.

Statistical analyses were performed using SAS V9.4 (Cary, NC) and SPSS V24 (Armonk, NY) P-values <0.05 were considered statistically significant.

Results:

There were 24,732 admissions in the pre-period and 25,536 admissions in the post-period after CP were discontinued. In the pre-period, approximately 12% admissions were isolated for MRSA and/or VRE, and the monthly rate remained relatively constant. No patients were isolated for MRSA/VRE in the post period. 835 adverse events occurred in the pre-period and 765 adverse events occurred in the post-period. The events were divided into infections and noninfectious adverse events. Demographics of patients with an adverse event are displayed in Table 2.

Noninfectious adverse events declined after CP were discontinued from 12.3 to 10.0 events per 1,000 admissions (p=0.022), which is a 19% decrease in noninfectious adverse events after 1 year. There was no statistically significant change in infectious adverse events (20.7 to 19.4 per 1,000 admissions, p=0.33) (Figure 1).

There was no level change after the intervention on rate of hospital adverse events. The monthly incidence rate ratio for noninfectious adverse events was 1.02 (95% CI 0.71–1.46, p=0.913) and for infectious adverse events, it was 1.31 (95% CI 1.00–1.71, p=0.051), indicating no significant change in rate immediately after CP were removed.

The slope change was significant for noninfectious adverse events and demonstrated a decrease in monthly events after the CP change with an incidence rate ratio of 0.94 (95% CI 0.90–0.99, p=0.028) (Figure 1). There was no significant slope change for infectious adverse events and the monthly incidence rate ratio was 0.99 (95% CI 0.95–1.02, p=0.43).

Each adverse event in the composite endpoints was evaluated individually, accounting for repeated observations in the same person in the model (Table 3). Although there were trends toward fewer falls and trauma, post-operative hemorrhage and/or hematoma, pressure ulcers, and PE/DVT, these were not statistically significant. Even though there was no change to overall infectious adverse events, SSI decreased by 24% after CP were discontinued, from 5.2 to 4.0 events per 1,000 admissions (p=0.03). There was a trend toward an increase in CLABSI, postoperative sepsis, and VAP, but these changes were small and not statistically significant.

The slope change was calculated for each adverse event as well. The slope change was significant for postoperative hemorrhage and hematoma, SSI, and demonstrated a decline in monthly events after the CP change for both adverse events (Table 3). The slope change was not significant for the remaining adverse events.

There were no significant level changes for any individual adverse events, except hospital onset C. difficile (data not shown). There was an initial increase in C. difficile after the policy change with an incidence rate ratio of 1.96 (95% CI 1.23–3.14, p=0.005), but after the initial increase, the rate declined and was similar to prior to the intervention.

The CP status of each patient with a noninfectious adverse event was evaluated. When comparing patients with MRSA and/or VRE, who were isolated in the pre-period and not isolated in the post-period, there was a 72% decline in noninfectious adverse events (p<0.001) (Figure 2). This decline in rate was driven by falls and trauma, postoperative hemorrhage and/or hematoma, and DVT/PE, which had the largest declines in this population. There was no significant change for non-isolation patients, who remained off precautions in both the pre and post periods (Table 4). Patients on either “other isolation” or “combination isolation” remained in isolation for both the pre and post period. The sample sizes were small (<2% of admissions) and there were very few noninfectious adverse events in these groups, leading to no statistically significant change in noninfectious adverse events after CP were discontinued (data not shown).

Discussion:

Controversy surrounds both the efficacy and patient harms associated with CP. Recent data suggests that discontinuing routine CP for MRSA and VRE can be performed without increasing healthcare associated infections with these organisms, but it has been unclear whether removing CP reduces overall patient harms.^3,6–8 This study demonstrated that removing routine CP for MRSA and VRE was associated with a decline in noninfectious adverse events, including falls and trauma, post operative hemorrhage and/or hematoma, wound dehiscence, pressure ulcers, and PE/DVTs. None of the secondary endpoints were statistically significant, which is likely due to the low overall rates of the individual events. This data supports prior research indicating that the use of CP can be a barrier to access to healthcare providers and that this can impact adverse event rates.

Importantly, the populations with the largest decline in noninfectious adverse events were the patients that have MRSA and VRE, but were no longer isolated in the post period. While this population was isolated, the average rate of noninfectious adverse events was 21.4 per 1,000 MRSA/VRE admissions and after the policy change, the adverse event rate decreased to 6.08 per 1,000 MRSA/VRE admissions. While one could argue that the decline in adverse events was multifactorial and may have been due to other quality improvement interventions, the large decline in noninfectious adverse events was only seen in the MRSA/VRE population, and not in the “no isolation” group. In addition, figure 2b shows that the decline started shortly after the policy change and the lower rate remained months after the intervention. There was also no change in the other isolation statuses that remained in isolation in the post period, but events in these populations were rare, making it difficult to fully assess.

In our prior study, we showed that MRSA and VRE clinical cultures, as a marker of healthcare associated infections, did not increase after CP were discontinued and CHG bathing was expanded to all units.⁶ This study further demonstrated that other reportable infectious adverse events did not increase after CP were discontinued, including infections with other organisms and device associated infections. Prior to this data, there was a theoretical concern that having fewer patients on CP could lead to increases in hospital acquired infections, but this study did not show an increase after the policy change. This may be due to the other horizontal infection prevention strategies, including near universal CHG bathing and our high hand hygiene rate (over 90%). This study also showed a significant decline in SSI after the policy was changed. The reason for the improvement is unclear and it may be related to improved access to healthcare providers, decreased microbial burden from expanded CHG bathing, or both. Further research is needed in this area.

While these initial data are encouraging, there are some limitations. First, this study was performed at a single, acute care hospital with single patient rooms and a hand hygiene compliance rate (>90%).⁶ It is unclear if the data on infectious adverse events are generalizable to other hospitals with shared patient rooms or a lower hand hygiene rate. Further research in other hospitals is necessary to determine the additional factors necessary for this to be successful.

Our institution also has a robust quality department, focused on reducing adverse events. Although no specific hospital wide interventions occurred during the time of this study, it is unclear if the results are generalizable to other institutions that do not have established programs focused on reducing falls, DVTs, post surgical adverse events, etc. In order to see a significant decline in noninfectious adverse events in MRSA/VRE patients, a combination of quality improvement strategies and removal of CP may be necessary to improve outcomes and further research in this area should be explored.

This study was quasi-experimental, and therefore, it is not possible to demonstrate causality. Although the data suggest that removing CP and expanding CHG bathing contributed a decline in noninfectious adverse events, further research is necessary with a more robust study design, such as a prospective, randomized control trial or a cross-over study.

In order to determine the composite end-points, our team reviewed the list of all reportable events and selected the events that have a plausible link with healthcare worker contact time. Although our team considered this list thoughtfully, it is unclear how many of these events are truly due to lack of healthcare contact given the amount of time each spent with their providers was not evaluated in this study. These events, in general, are all likely multifactorial and contact with providers is likely just one factor.

The data used were also collected for public reporting and not specifically for research or patient care. While this is generalizable to other hospitals that report based on the same definitions, the data are collected based on reporting criteria and may not capture all actual events. While this is a limitation, it likely impacted both the pre and post periods equally since the definitions have been constant.

In order to determine which patients would have qualified for MRSA/VRE in the post period, we used specific criteria that would have triggered an isolation alert in the pre-period. There are some limitations to this approach. First, it is possible that a patient had history of MRSA/VRE from another hospital that would have been missed in the post period, but this group likely represents only a small portion of the MRSA/VRE population. It is also possible that some VRE patients may have been missed given routine screening was no longer performed in the post period (1.3% of patients were VRE screen positive in the pre-period). MRSA screening was continued in the post period, however, given California mandate, so this is likely more accurate. Although incorrect isolation status is a concern, it is likely only a small portion of the patients and even if patients were missed, the overall rate of noninfectious adverse events did decline.

This study showed that one year after discontinuing routine CP for endemic MRSA and VRE and expansion of CHG bathing, there was a significant decline in noninfectious adverse events, with the largest decline in patients who no longer required isolation for MRSA and VRE. There also was no increase in infectious adverse events, including device-associated infections. These data and prior data indicating that the removal of routine CP can be performed without an increase in infectious complications suggest that removal of MRSA/VRE CP can contribute to improved patient safety and reduction of preventable adverse events.^6–8 Further data are necessary on the optimal hospital conditions and quality improvement programs necessary to make this successful. Given CP are likely still necessary for specific populations, strategies to increase contact with healthcare providers and decrease noninfectious adverse events in these patients should be developed.