This review investigated effects of ambient, architectural or interior design features of health care settings on health and well-being. The authors concluded that features of the physical health care environment affect the well-being of patients, but evidence for the effects of specific environmental stimuli is limited. The authors' cautious conclusions reflect the limitations of the evidence presented and appear appropriate.

To assess the effects of physical environmental stimuli in health care settings on the health and well-being of patients.

MEDLINE, PsycINFO, EMBASE, CINAHL, ICONDA, ScienceDirect, Compendex and the ISI Citation Indexes were searched up to the summer of 2005. Articles with an abstract in English, German, Spanish, French or Dutch were included. The search strategy used was described. The reference lists of published reviews were also screened.

Studies were eligible for the review if they were controlled trials comparing an intervention involving an environmental stimulus in a health care setting with another environmental stimulus, or no environmental stimuli at all, and reported a health-related outcome or outcomes. Environmental stimuli were defined as ambient, architectural or interior design features that are intended purely to provide a stimulus and that influence patients through mediation by psychological processes. Studies that used environmental stimuli as treatments were excluded. The interventions in the included studies related to multiple stimuli (e.g. redecoration or renovation of wards, treatment areas or waiting rooms), ambient features (e.g. exposure to sunlight, sound or odour), architectural features or interior design features. The participants included patients in a wide range of in- and out-patient settings, and many diverse clinical and psychological outcomes were evaluated. Studies were excluded if environmental interventions were confounded with non-environmental changes.

The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.

Methodological characteristics of the included studies (study design, randomisation, comparability of the groups and reliability of outcome measures) were briefly discussed in the text but no details (other than study design) were provided for individual studies.

The authors did not state how the validity assessment was performed.

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction.

The data were synthesised narratively and summarised in tables by type of stimulus (multiple stimuli, ambient features, architectural features and interior design features).

Thirty studies were included in the review: 2 randomised controlled trials (RCTs; n=130), 19 non-randomised controlled trials (n=3,290) and 9 studies (n=1,992) described as 'natural experiments' (six of which were conducted retrospectively).

Studies of multiple stimuli found inconsistent effects of redecoration and renovation on health-related outcomes (11 studies). Studies of ambient features found positive effects of sunlight (4 studies) and interventions to reduce the negative effects of noise (4 studies). The presence of windows and a natural view had positive effects on outcomes such as delirium, sleep and length of stay, whereas the effects of spatial layout were inconsistent (3 studies). In one RCT assessing interior design features, pain control during flexible bronchoscopy was better when patients were exposed to natural murals and taped nature sounds.

Features of the physical health care environment affect the well-being of patients, but evidence for the effects of specific environmental stimuli is limited and difficult to generalise.

This review had clear inclusion criteria, although criteria for the participants and outcomes were broad. The authors searched a range of relevant sources. Some language restrictions were imposed and unpublished studies were not sought, so it is possible that some relevant studies could have been missed. The risk of publication bias was not assessed. The methods used to select the studies and extract the data were not reported, so the risk of bias and errors arising during the review process is uncertain. Methodological characteristics of the included studies were discussed but details were not presented, which makes it difficult to assess the quality of the included studies and the synthesis derived from them. Other relevant details of the included studies were reported. The narrative synthesis was appropriate in view of the heterogeneity of the interventions, participants and outcomes included in the review. The authors' categorisation of the studies by type of environmental stimulus appeared sensible, but differences between the studies limited the degree of synthesis that was possible within categories. The authors' cautious conclusions reflect the limitations of the evidence presented and appear appropriate.

Practice: The authors did not state any implications for practice.

Research: The authors stated that further well-conducted trials are needed to address the effects of specific environmental features on health-related outcomes and also to study interactions between different stimuli.

Not stated.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.