Are the outcomes of clinical pathways evidence-based? A critical appraisal of clinical pathway evaluation research

Aim and objective To evaluate the validity of study outcomes of published papers that report the effects of clinical pathways (CP). Method Systematic review based on two search strategies, including searching Medline, CINAHL, Embase, Psychinfo and Picarta from 1995 till 2005 and ISI Web of Knowledge (SM). We included randomized controlled or quasi-experimental studies evaluating the efficacy of clinical pathway application. Assessment of the methodological quality of the studies included randomization, power analysis, selection bias, validity of outcome indicators, appropriateness of statistical tests, direct (matching) and indirect (statistical) control for confounders. Outcomes included length of stay, costs, readmission rate and complications. Two reviewers independently assessed the methodological quality of the selected papers and recorded the findings with an evaluation tool developed from a set of items for quality assessment derived from the Cochrane Library and other publications. Results The study sample comprised of 115 publications. A total of 91.3% of the studies comprised of retrospective studies and 8.7% were randomized controlled studies. Using a quality-scoring assessment tool, 33% of the papers were classified as of good quality, whereas 67% were classified as of low quality. Of the studies, 10.4% controlled for confounding by matching and 59.1% adopted parametric statistical tests without testing variables on normal distribution. Differences in outcomes were not always statistically tested. Conclusion Readers should be cautious when interpreting the results of clinical pathway evaluation studies because of the confounding factors and sources of contamination affecting the evidence-based validity of the outcomes.