The representation of vulnerable populations in quality improvement studies

A mapping review to quantify representation of vulnerable populations, who suffer from disparity and often inequitable healthcare, in quality improvement (QI) research.

Studies published in 2004-2014 inclusive from Medline, Embase and Cochrane databases for English language research with the terms 'quality improvement' or 'quality control' or 'QI' and 'plan-do-study-act' or 'PDSA' in the years 2004-2014 inclusively.

Published clinical research that was a QI-themed, as identified by its declared search terms, MESH terms, abstract or title.

Three reviewers identified the eligible studies independently. Excluded were publications that were not trials, evaluations or analyses.

Of 2039 results, 1660 were eligible for inclusion. There were 586 (33.5%) publications that targeted a specific vulnerable population: children (184, 10.54%), mental health patients (125, 7.16%), the elderly (100, 5.73%), women (57, 3.27%), the poor (30, 1.72%), rural residents (29, 1.66%), visible minorities (27, 1.55%), the terminally ill (17, 0.97%), adolescents (16, 0.92%) and prisoners (1 study). Seventy-four articles targeted two or more vulnerable populations, and 11 targeted three population categories. On average, there were 158 QI research studies published per year, increasing from 69 in 2004 to 396 in 2014 (R2 = 0.7, P < 0.001). The relative representation of vulnerable populations had a mean of 33.58% and was stable over the time period (standard deviation (SD) = 5.9%, R2 = 0.001). Seven countries contributed to over 85% of the publications targeting vulnerable populations, with the USA contributing 62% of the studies.

Over 11 years, there has been a marked increase in QI publications. Roughly one-third of all published QI research is on vulnerable populations, a stable proportion over time. Nevertheless, some vulnerable populations are under-represented. Increased education, resources and attention are encouraged to improve the health of vulnerable populations through focused QI initiatives.