Chiropractic care for nonmusculoskeletal conditions: a systematic review with implications for whole systems research.
(1) To evaluate the evidence on the effect of chiropractic care, rather than spinal manipulation only, on patients with nonmusculoskeletal conditions; and (2) to identify shortcomings in the evidence base on this topic, from a Whole Systems Research perspective. Systematic review. Databases included were PubMed, Ovid, Mantis, Index to Chiropractic Literature, and CINAHL. Search restrictions were human subjects, peer-reviewed journal, English language, and publication before May 2005. All randomized controlled trials (RCTs) were evaluated using the Scottish Intercollegiate Guidelines Network (SIGN) and Jadad checklists; a checklist developed from the CONSORT (Consolidated Standards of Reporting Trials) guidelines; and one developed by the authors to evaluate studies in terms of Whole Systems Research (WSR) considerations. The search yielded 179 papers addressing 50 different nonmusculoskeletal conditions. There were 122 case reports or case series, 47 experimental designs, including 14 RCTs, 9 systematic reviews, and 1 a large cohort study. The 14 RCTs addressed 10 conditions. Six RCTs were rated "high" on the 3 conventional checklists; one of these 6 was rated "high" in terms of WSR considerations. (1) Adverse effects should be routinely reported. For the few studies that did report, adverse effects of spinal manipulation for all ages and conditions were rare, transient, and not severe. (2) Evidence from controlled studies and usual practice supports chiropractic care (the entire clinical encounter) as providing benefit to patients with asthma, cervicogenic vertigo, and infantile colic. Evidence was promising for potential benefit of manual procedures for children with otitis media and elderly patients with pneumonia. (3) The RCT design is not necessarily incompatible with WSR. RCTs could improve generalizability by basing protocols on usual practice. (4) Case reports could contribute more to WSR by increasing their emphasis on patient characteristics and patient-based outcomes. (5) Chiropractic investigators, practitioners, and funding agencies should increase their attention to observational designs.