The relationship between linkage refusal and selected health conditions of survey respondents.

To maximize limited resources and reduce respondent burden, there is an increased interest in linking population health surveys with other sources of data, such as administrative records. Health differences between adults who consent to and refuse linkage could bias study results with linked data. National Health Interview Survey (NHIS) data are routinely linked to administrative records from the Social Security Administration and the Centers for Medicare and Medicaid Services. Using the NHIS 2010-2013, we examined the association between selected health conditions and respondents' linkage refusal. Linkage refusal was significantly lower for adults with serious psychological distress, chronic obstructive pulmonary disease, diabetes, heart disease, stroke, hypertension, and cancer compared to those without these conditions. Linkage refusal decreased as the number of conditions increased and health status decreased. Our finding that linkage consent was associated with respondents' health characteristics suggests that researchers should try to address potential linkage bias in their analyses.