Relationship between hospital ward design and healthcare-associated infection rates: a systematic review and meta-analysis

Stiller, Andrea; Salm, Florian; Bischoff, Peter; Gastmeier, Petra

This review has several limitations. It cannot be ruled out that due to the before-/after-intervention concept the general improvement of medical care over time might have biased the results of some of the studies and consequently biased the results of our meta-analysis (see Figs. 4, 5 and 6). This does not affect three studies [16] [17] [18] . Two of these three studies comparing the intervention and control group in the same time period also revealed a benefit in single patient rooms [17, 18] . The study conducted by Ellison et al. is found to be the only statistical outlier [16] . Confirmatively, the authors describe what may have compromised the intervention's potential: shortly after the study began, three single-patient rooms were converted to multi-patient rooms with proximity of 1m between beds. Approximately 50% of the intervention group's patients stayed in these converted rooms. The considerable heterogeneity in the meta-analysis of studies comparing single vs. multi-bedrooms with the outcome of healthcare-associated colonization/infection could be partially explained by the study design. Hagel et al. considered a strong Hawthorne effect on hand hygiene performance, which might attenuate the reported results regarding hand hygiene compliance rate [37] .