Item nonresponse to psychosocial questionnaires was associated with higher mortality after acute myocardial infarction

Objective — To examine the relationship between selective nonresponse to a psychosocial questionnaire and mortality after acute myocardial infarction (AMI).

Study Design and Setting — Two thousand six hundred and ninety AMI survivors after AMI hospitalization were recruited to complete a 30-day follow-up interview. Patients were classified into four groups (survey nonparticipation and complete, partial, and no item nonresponse) according to their degree of response to the Medical Outcomes Study (MOS) Social Support Survey (MOS-SSS). Cox proportional hazard models, adjusted for baseline sociodemographic, clinical, and psychosocial (i.e., social isolation) characteristics, were used to examine all-cause mortality, 3 years post-AMI, across the response levels.

Results — 13.9% of the eligible patients refused follow-up participation; MOS-SSS item nonresponse was present in up to 14.7% of participants and was more frequent among the elderly, socially disadvantaged, and those with higher clinical risk. A nonresponse mortality gradient existed, ranging from 8.9% (no item nonresponse) to 18.7% (complete item nonresponse) (P<0.001). After adjusting for baseline characteristics, complete item nonresponse remained significantly associated with mortality (hazard ratio: 1.33; 95% confidence interval: 1.02-1.73).

Conclusions — Item nonresponse to a social support questionnaire is associated with higher mortality post-AMI. Although explanatory factors may include age and baseline clinical risk, additional psychosocial and/or unmeasured factors may account for the poorer prognosis.