Methodological and Reporting Quality of Comparative Studies Evaluating Health-Related Quality of Life of Colorectal Cancer Patients and Controls: A Systematic Review

BACKGROUND: Health-related quality of life is an important outcome measure in patients with colorectal cancer. Comparison with normative data has been increasingly undertaken to assess the additional impact of colorectal cancer on health-related quality of life. OBJECTIVE: This review aimed to critically appraise the methodological details and reporting characteristics of comparative studies evaluating differences in health-related quality of life between patients and controls. DATA SOURCES: A systematic search of English-language literature published between January 1985 and May 2014 was conducted through a database search of PubMed, Web of Science, Embase, and Medline. STUDY SELECTION: Comparative studies reporting health-related quality-of-life outcomes among patients who have colorectal cancer and controls were selected. MAIN OUTCOME MEASURES: Methodological and reporting quality per comparison study was evaluated based on a 11-item methodological checklist proposed by Efficace in 2003 and a set of criteria predetermined by reviewers. RESULTS: Thirty-one comparative studies involving > 10,000 patients and > 10,000 controls were included. Twenty-three studies (74.2%) originated from European countries, with the largest number from the Netherlands (n = 6). Twenty-eight studies (90.3%) compared the health-related quality of life of patients with normative data published elsewhere, whereas the remaining studies recruited a group of patients who had colorectal cancer and a group of control patients within the same studies. The European Organisation for Research and Treatment of Cancer Quality-of-Life Questionnaire Core 30 was the most extensively used instrument (n = 16; 51.6%). Eight studies (25.8%) were classified as probably robust for clinical decision making according to the Efficace standard methodological checklist. Our further quality assessment revealed the lack of score differences reported (61.3%), contemporary comparisons (36.7%), statistical significance tested (38.7%), and matching of control group (58.1%), possibly leading to inappropriate control groups for fair comparisons. LIMITATIONS: Meta-analysis of differences between the 2 groups was not available. CONCLUSIONS: In general, one-fourth of comparative studies that evaluated health-related quality of life of patients who had colorectal cancer achieved high quality in reporting characteristics and methodological details. Future studies are encouraged to undertake health-related quality-of-life measurement and adhere to a methodological checklist in comparison with controls.