Is chiropractic evidence based? A pilot study

To calculate the proportion of care delivered in a chiropractic practice supported by good-quality clinical trials.

Retrospective survey.

Data were collected from patient files relating to 180 consecutive patient visits in a suburban chiropractic practice in northern Spain. Each patient's presenting complaint was paired with the chiropractor's chosen primary intervention. Based on a literature review (Medline, Mantis, and nonautomated searches of local medical libraries), each presenting complaint-primary intervention pairing was categorized according to the level of supporting evidence as follows: Category I, intervention based on good quality clinical trial evidence; Category II, intervention based on poor-quality or no clinical trial evidence. To distinguish between good- and poor-quality clinical trials, studies were critically appraised and assigned quality scores.

Of the 180 cases surveyed, 123 (68.3%) (95% CI, 61.5%-75.1%) were based on clinical trials of good methodologic quality (Category I). Only 57 (31.7%) (95% CI, 24.9%-38.5%) of the cases were based on poor-quality or no clinical trial evidence (Category II).

When patients were used as the denominator, the majority of cases in a chiropractic practice were cared for with interventions based on evidence from good-quality, randomized clinical trials. When compared to the many other studies of similar design that have evaluated the extent to which different medical specialties are evidence based, chiropractic practice was found to have the highest proportion of care (68.3%) supported by good-quality experimental evidence.