Feasibility of using recipients of health promotional newsletters for post-marketing surveillance

Achieving an adequate sample size is one of the major difficulties in perfo rming post-marketing observational studies of health outcomes in persons ta king specific drug preparations. We assessed the feasibility of recruiting participants for such a study of Cardizem(R) CD from approximately 400,000 U.S. recipients of a health promotion newsletter. A three-page questionnair e was sent to a 2.5% random sample (n = 10,000) of recipients, stratified b y geographic region. After two mailings, 2779 (28%) returned the questionna ire. Of the 2779 respondents, 2132 (77%) reported having high blood pressur e. Eighty-seven percent indicated a willingness to participate in a long-te rm prospective study. In a multivariate model, calcium channel blocker (CCB ) use was associated with a history of coronary heart disease, duration of hypertension medication use greater than 1 year, a rating of good or excell ent hypertension care, higher systolic blood pressure, higher education lev el, family history of cardiovascular disease, and history of smoking. These results indicate that self-reported CCB users may be at greater risk of ca rdiovascular heart disease and that it is feasible to use health promotion newsletters as a source of participants in prospective studies of cardiovas cular disease. (C) 2000 Elsevier Science Inc. All rights reserved.