Does the prevention of complications explain the survival benefit of organized inpatient (stroke unit) care? - Further analysis of a systematic review

Background and Purpose - Systematic reviews have shown that organized inpatient (stroke unit) care reduces the risk of death after stroke. However, it is unclear how this is achieved. We tested whether stroke unit care could reduce deaths by preventing complications. Methods - We updated a collaborative systematic review of 31 controlled clinical trials (6936 participants) to include reported interventions and complications during early hospital care plus the certified cause of death during follow up. Each secondary analysis used data from between 7 and 17 studies (1652 to 3327 participants). Complications were grouped as physiological, neurological, cardiovascular, complications of immobility, and others. Bayesian hierarchical models were used to estimate odds ratios for features occurring in stroke units versus conventional care. Results - Based on the data of 17 trials (3327 participants), organized (stroke unit) care reduced case fatality during scheduled follow up (OR: 0.75; 95% credible intervals: 0.59 to 0.92), in particular deaths certified as attributable to complications of immobility (0.59; 0.41 to 0.86). Stroke unit care was associated with statistically significant increases in the reported use of oxygen (2.39; 1.39 to 4.66), measures to prevent aspiration (2.42; 1.36 to 4.36), and paracetamol (2.80; 1.14 to 4.83) plus a nonsignificant reduction in the use of urinary catheterization. Stroke units were associated with statistically significant reductions in stroke progression/recurrence (0.66; 0.46 to 0.95) and in some complications of immobility: chest infections (0.60; 0.42 to 0.87), other infections (0.56; 0.40 to 0.84), and pressure sores (0.44; 0.22 to 0.85). There were no significant differences in cardiovascular, physiological, or other complications. Conclusions - Organized inpatient (stroke unit) care appears to reduce the risk of death after stroke through the prevention and treatment of complications, in particular infections.