Impact of benzodiazepines on functional outcome and occurrence of pneumonia in stroke: evidence from VISTA

Pre-morbid sleep disturbance and its association with stroke severity: results from the international INTERSTROKE study

BACKGROUND AND PURPOSE

Whilst sleep disturbances are associated with stroke, their association with stroke severity is less certain. In the INTERSTROKE study, the association of pre-morbid sleep disturbance with stroke severity and functional outcome following stroke was evaluated.

METHODS

INTERSTROKE is an international case-control study of first acute stroke. This analysis included cases who completed a standardized questionnaire concerning nine symptoms of sleep disturbance (sleep onset latency, duration, quality, nocturnal awakening, napping duration, whether a nap was planned, snoring, snorting and breathing cessation) in the month prior to stroke (n = 2361). Two indices were derived representing sleep disturbance (range 0-9) and obstructive sleep apnoea (range 0-3) symptoms. Logistic regression was used to estimate the magnitude of association between symptoms and stroke severity defined by the modified Rankin Score.

RESULTS

The mean age of participants was 62.9 years, and 42% were female. On multivariable analysis, there was a graded association between increasing number of sleep disturbance symptoms and initially severe stroke (2-3, odds ratio [OR] 1.44, 95% confidence interval [CI] 1.07-1.94; 4-5, OR 1.66, 95% CI 1.23-2.25; >5, OR 2.58, 95% CI 1.83-3.66). Having >5 sleep disturbance symptoms was associated with significantly increased odds of functional deterioration at 1 month (OR 1.54, 95% CI 1.01-2.34). A higher obstructive sleep apnoea score was also associated with significantly increased odds of initially severe stroke (2-3, OR 1.48; 95% CI 1.20-1.83) but not functional deterioration at 1 month (OR 1.19, 95% CI 0.93-1.52).

CONCLUSIONS

Sleep disturbance symptoms were common and associated with an increased odds of severe stroke and functional deterioration. Interventions to modify sleep disturbance may help prevent disabling stroke/improve functional outcomes and should be the subject of future research.

Effect of alteplase, benzodiazepines and beta-blocker on post-stroke pneumonia: Exploration of VISTA-Acute

BACKGROUND

Post-stroke pneumonia is a frequent complication of stroke and is associated with high mortality. Investigators have described its associations with beta-blocker. However, there has been no evaluation of the role of recombinant tissue plasminogen activator (RTPA). We postulate that RTPA may modify the effect of stroke on pneumonia by reducing stroke disability. We explore this using data from neuroprotection trials in Virtual International Stroke Trials Archive (VISTA)-Acute.

METHOD

We evaluated the impact of RTPA and other medications in random forest model. Random forest is a type of supervised ensemble tree-based machine learning method. We used the standard approach for performing random forest and partitioned the data into training (70%) and validation (30%) sets. This action enabled to the model developed on training data to be evaluated in the validation data. We borrowed idea from Coalition Game Theory on fair distribution of marginal profit (Shapley value) to determine proportional contribution of a covariate to the model. Consistent with other analysis using the VISTA-Acute data, the diagnosis of post-stroke pneumonia was based on reports of serious adverse events.

RESULTS

The overall frequency of pneumonia was 10.9% (614/5652). It was present in 11.5% of the RTPA (270/2358) and 10.4% (344/3295) of the no RTPA groups. There was significant (p<0.05) imbalance in covariates (age, baseline National Institutes of Health Stroke Scale (NIHSS), diabetes, and sex). The AUC for training data was 0.70 (95% CI 0.65-0.76), validation data was 0.67 (95% CI 0.62-0.73). The Shapley value shows that baseline NIHSS (≥10) and age (≥80) made the largest contribution to the model of pneumonia while absence of benzodiazepine may protect against pneumonia. RTPA and beta-blocker had very low effect on frequency of pneumonia.

CONCLUSION

In this cohort pneumonia was strongly associated with stroke severity and age whereas RTPA had a much lower effect. An intriguing finding is a possible association between benzodiazepine and pneumonia but this requires further evaluation.

Association between benzodiazepine use and risks of chronic-onset poststroke pneumonia: a population-based cohort study

OBJECTIVES

To investigate the association between benzodiazepine (BZD) use and the risk of chronic-onset poststroke pneumonia.

DESIGN

Population-based propensity-matched retrospective cohort study.

SETTING

Taiwan's National Health Insurance Research Database.

PARTICIPANTS

Patients newly diagnosed with stroke between 2000 and 2012 were identified and, after propensity score matching, 7516 patients were enrolled. Among these, 3758 patients received BZDs after stroke while 3758 did not.

OUTCOME MEASURES

HRs for developing pneumonia over 1 month after stroke according to BZD use were assessed using Cox proportional hazards regression models. Analyses according to cumulative defined daily doses (cDDDs) of BZDs and stratification for age and sex were also performed.

RESULTS

During a mean follow-up time of 4.4 years, 1027 patients in the BZD cohort and 478 patients in the non-BZD cohort developed pneumonia over 1 month after stroke. Patients using BZDs after stroke had a higher pneumonia risk than did those not using BZDs (52.2vs32.6 per 1000 person-years, adjusted HR (aHR)=2.21, 95% CI (CI)=1.97 to 2.48, p<0.001). Analyses based on cumulative BZD dose revealed that all BZD user subgroups were associated with a higher risk of pneumonia. The aHRs for patients taking 1-90, 91-365 and >365 cDDDs of BZDs were 2.28 (95% CI=2.01 to 2.58; p<0.001), 2.09 (95% CI=1.77 to 2.47; p<0.001) and 2.08 (95% CI=1.72 to 2.52; p<0.001), respectively. The significant association between BZD use and increased pneumonia risk persisted even after stratifying subgroups by age and sex.

CONCLUSIONS

BZD use is associated with an increased risk of chronic-onset poststroke pneumonia.

Preadmission use of benzodiazepines and stroke outcomes: the Biostroke prospective cohort study

OBJECTIVES

We tested the hypothesis that stroke outcomes in patients with preadmission use of benzodiazepine are worse.

METHOD

In a prospective cohort study, we recruited patients with acute ischaemic stroke. Mortality, functional outcomes and cognition were evaluated at 8 and 90 days after stroke.

RESULTS

370 patients were included. 62 (18.5%) of the 336 remaining patients were treated with benzodiazepines when stroke occurred, and they did not receive any other psychotropic drug. The mortality rate was higher in benzodiazepines users than non-users at day 8 (2.2% vs 8.1%, p=0.034) and day 90 (8.1% vs 25.9%, p=0.0001). After controlling for baseline differences using propensity-score matching, only the difference in mortality rate at day 90 was of borderline of significance, with a matched OR of 3.93 (95% CI, 0.91 to 16.98). In propensity-score-adjusted cohort, this difference remained significant with a similar treatment effect size (adjusted OR, 3.50; 95% CI, 1.57 to 7.76). A higher rate of poor functional outcome at day 8 and day 90 defined bymodified Rankin scale (mRS) ≥2 or by theBarthel index (BI) <95 was found in benzodiazepines users. In propensity-score-adjusted cohort, only the difference in mRS≥2 at day 90 remained significant (adjusted OR, 1.89; 95% CI, 1.02 to 3.48). In survivors at day 8 and at day 90, there was no significant difference in cognitive evaluation.

CONCLUSION

Our study has shown that preadmission use of benzodiazepines could be associated with increased post-stroke mortality at 90 days. These findings do not support a putative neuroprotective effect of γ-aminobutyric acid_A receptors agonists and should alert clinicians of their potential risks.

TRIAL REGISTRATION NUMBER

NCT00763217.