Studies on infectious diseases, neurology, and more

Isolation precautions may not always be of benefit.


Isolation precautions associated with increases in length of stay and cost

Inpatients on isolation precautions due to respiratory illness or methicillin-resistant Staphylococcus aureus (MRSA) had longer hospital stays and higher costs of care than similar non-isolated patients, a recent study found.

The retrospective cohort study was conducted on the general internal medicine services of three academic hospitals in Toronto, Canada, between January 2010 and December 2012. The researchers identified 1,506 patients who had been isolated for respiratory illness and 745 who had been isolated for MRSA. They were matched to controls, who were hospitalized but not isolated, based on propensity scores. Results were published online by the Journal of General Internal Medicine on Oct. 17, 2016.

Compared to non-isolated patients, patients on isolation for respiratory illnesses stayed 17% longer, while MRSA patients stayed 30% longer. Both isolated groups also exceeded their expected length of stay, respiratory illness patients by 9% and MRSA patients by 13%. Isolation was also associated with increased cost of care: 23% in the respiratory patients and 13% in the MRSA patients. Another significant difference associated with isolation, only found in the MRSA patients, was a 4.4% higher risk of 30-day readmission. The study also looked at ED visits within 30 days, adverse events, in-hospital mortality, and patient complaints and found no significant associations with isolation.

Given the lack of evidence on whether precautions for respiratory illnesses actually reduce nosocomial spread, it's difficult to assess whether the benefits outweigh the observed costs of isolation, the study authors said. Isolation for MRSA has shown effectiveness for reducing transmission, they noted. However, other research has shown additional ways in which isolation precautions negatively impact care, including psychological effects, fewer contacts with clinicians, and greater inpatient deconditioning.

The generalizability of the study is limited by its setting in academic hospitals in Toronto and, despite the propensity matching, the results could have been confounded by greater illness in patients with MRSA compared to other similar infections, the authors noted. “Balancing the benefits for the many with the harms to the few is a future challenge for hospital isolation practices,” they wrote.

Benefits of clopidogrel for secondary stroke prevention vary with renal function

After a minor ischemic stroke or high-risk transient ischemic attack, patients with moderate chronic kidney disease (CKD) saw no benefit from adding clopidogrel to aspirin therapy, a recent analysis found.

The findings were based on a post hoc analysis of the CHANCE study, a multicenter randomized trial in China in which patients who had a minor ischemic stroke or high-risk transient ischemic attack were given either clopidogrel (initial clopidogrel dose of 300 mg, followed by 75 mg/d for 90 days) plus aspirin (75 mg/d for the first 21 days) or placebo plus aspirin (75 mg/d for 90 days). This analysis stratified 5,150 patients by estimated glomerular filtration rate (eGFR), of which 53% had normal renal function (eGFR ≥90 mL/min per 1.73 m2), 40.1% had mild CKD (eGFR of 60 to 89 mL/min per 1.73m2), and 6.9% had moderate CKD (eGFR <60 mL/min per 1.73 m2).

Adding clopidogrel to aspirin was associated with lower risk of having a stroke within 90 days in patients with normal renal function and in those with mild CKD; however, in patients with moderate CKD, no stroke prevention benefit was associated with clopidogrel (hazard ratios: 0.77 [95% CI, 0.60 to 0.98], 0.60 [95% CI, 0.45 to 0.79], and 1.00 [95% CI, 0.43 to 2.35], respectively). The study excluded patients with creatinine more than 1.5 times the upper normal limit, so no data were available on patients with more severe CKD.

This analysis also looked at bleeding episodes and found no differences in that outcome associated with category of renal function. The study authors concluded that adding clopidogrel to aspirin reduced 90-day stroke risk in patients with normal renal function and mild renal insufficiency, a finding that was in accordance with the overall results of the CHANCE study. However, the lack of benefit in patients with moderate CKD and the absence of bleeding risk differed from some other previous research, the authors noted.

The results of this analysis may differ from others because of heterogeneous study populations, and this study was limited by its inclusion of relatively fewer patients with moderate CKD (n=354). The results should be interpreted with caution and validated in prospective trials, the authors said. “However, because specific recommendations for antiplatelet therapy in patients with CKD plus ischemic stroke are not available, the present study may provide some valuable information for this special population,” they wrote. The study was published online by Stroke on Oct. 13, 2016, and appeared in the February 2017 issue.

Study links cardiac rehab after acute MI with lower mortality but not improved health outcomes

Although patients who participated in cardiac rehabilitation after discharge for acute myocardial infarction (AMI) saw survival benefits, they did not report better health status outcomes than nonparticipants, according to a recent study.

Using two national registries (PREMIER and TRIUMPH), researchers analyzed 4,929 patients with AMI (67.5% men; mean age, 60.0 years) who had baseline data, information on cardiac rehabilitation participation, and six to 12 months of follow-up health status data. Results were published online on Oct. 19, 2016, by JAMA Cardiology and appeared in the December 2016 issue.

Cardiac rehabilitation was defined as one session within six months of discharge. After propensity matching and excluding 23 patients who could not be matched, researchers compared patient-reported outcomes between 2,012 cardiac rehabilitation participants and 2,894 nonparticipants.

Primary outcomes, as measured by the Seattle Angina Questionnaire, were quality of life, angina frequency, treatment satisfaction, and physical limitation domain scores at six and 12 months after discharge. Secondary outcomes were mean differences in physical and mental component summary scores on the 12-Item Short-Form Health Survey, as well as all-cause mortality.

Both cohorts experienced improvements in health status outcomes in the 12 months after discharge, but there were no clinical differences between groups in the mean scores on both survey instruments. However, participation in cardiac rehabilitation was associated with a 41% lower hazard of all-cause mortality up to seven years after AMI (hazard rate, 0.59; 95% CI, 0.46 to 0.75).

“Although improvement in health status is a commonly cited benefit of participation in [cardiac rehabilitation] after AMI, our results and prior work underscore the paucity of data to support this statement,” the study authors wrote, adding that the potential survival benefit and underuse of cardiac rehabilitation are “compelling reasons” to refer patients to the therapy. They noted limitations to their observational study, such as the drawbacks of self-reported outcomes, the lack of more information about cardiac rehabilitation sessions, and the possibility of unmeasured confounding.

An accompanying editorial noted an additional limitation, that the registries enrolled patients between 2003 and 2008, so these results may not represent contemporary treatment patterns. The editorialist challenged the study's neutral results, reporting such “established salubrious effects of cardiac rehabilitation” as improved endothelial function, induced ischemic preconditioning, and reduced weight and inflammation.

In addition, it is controversial to ascribe the reduction in long-term mortality to cardiac rehabilitation participation, according to the editorial. “[Considering] the absence of more granularity on the cardiac rehabilitation program (i.e., type, intensity, duration, completion, and nonmonitored maintenance sessions), it is plausible that the mortality finding reflects the healthy participant bias,” the editorialist wrote.

Score predicts PCI complications for patients with chronic total occlusion

Researchers developed a new score for predicting periprocedural complications in patients with chronic total occlusion who undergo percutaneous coronary intervention (PCI).

The score was derived and validated using data from 1,569 chronic total occlusion PCIs, collected in an international registry. Forty-four (2.8%) of the patients experienced complications, and the researchers identified 3 factors that were independent predictors of complication: age older than 65 years (odds ratio [OR], 4.85; 95% CI, 1.82 to 16.77), lesion length of 23 mm or longer (OR, 3.22; 95% CI, 1.08 to 13.89), and use of the retrograde approach (OR, 2.41; 95% CI, 1.04 to 6.05).

Based on the findings, the score assigned 3 points for age older than 65 years, 2 points for lesion length of 23 mm or longer, and 1 point for use of the retrograde approach. Score values of 0 to 2, 3 to 4, and 5 or greater were defined as low, intermediate, and high risk of complications. The resulting score, which the authors called the PROGRESS CTO complication score, showed good calibration and discriminatory capacity in the derivation and validation sets. Results were published by the Journal of the American Heart Association on Oct. 11, 2016.

Other scores have been developed to predict the success or failure of these procedures, but a specific predictor of complications may be helpful, the study authors said. It “can significantly aid physician and patient decision making by allowing accurate determination of the risk/benefit ratio for each procedure” and can also help physicians “decide how aggressively to pursue angiographic success,” they wrote.

The study was limited by its observational design as well as the relatively low rate of complications in the cohort and needs external validation, the authors noted.