Adverse selection and moral hazard in the provision of clinical trial ancillary care.

As more and more clinical trials are conducted in developing countries, concerns arise about non-trial medical care available to study participants. Recent work argues for ancillary care - medical care not part of the clinical trial per se - to be formally incorporated into these studies. Although the provision of ancillary care is often justified on ethical grounds, a number of crucial implementation issues remain unresolved, including its scope, duration and financing. Drawing on lessons from health insurance benefit design, we highlight two overlooked challenges for ancillary care adoption - adverse selection and moral hazard - and offer recommendations that could attenuate their consequences. Specifically, adverse selection and moral hazard could be reduced by offering a choice between ancillary medical care and monetary compensation or rewarding low ancillary care utilization. Alternatively, researchers' financial risk due to ancillary care could be shifted to a third-party insurer. Recognizing participants' behavioral responses to prospective offers of ancillary medical care would allow funders and research teams to forecast the demand for ancillary care more accurately and to prepare for its provision more adequately.