Increased risk of exacerbating gastrointestinal disease among elderly patients following treatment with calcium channel blockers

Calcium channel blockers (CCBs) have been widely used for the treatment of hypertension and angina pectoris. It is presumed that CCBs decrease the lower esophageal sphincter pressure and as a result, the risk of gastrointestinal disease may be increased. Since the prevalence of gastrointestinal diseases has increased in elderly patients, it is possible that treatment with CCBs may have contributed to this increase. Therefore, we considered that the risk of exacerbating gastrointestinal disease among elderly patients by CCBs can be estimated by using the prescription ratio of antisecretory drugs as an outcome. We hypothesized that patients who are prescribed CCBs would increase the use of antisecretory drugs involving H-2-receptor antagonists and proton pump inhibitors (PPIs). From January 2001 to December 2005, a dynamic retrospective cohort study was performed at three community pharmacies in Nagasaki city, Japan, to assess the use of antisecretory drugs following treatment with CCBs among elderly patients. The correlation of initiation of antisecretory drugs treatment to maintenance therapy with PPIs was determined by the Cox proportional hazards model. The proposed study includes 303 patients prescribed CCBs and 258 controls. During the study period, 138 patients prescribed CCBs and 66 controls were initiated by giving antisecretory drugs; the hazard ratio was 1.40 (95% confidence interval 1.21-1.63). Eighty two patients taking CCBs and 32 controls were initiated by the maintenance therapy with PPIs; the hazard ratio was 1.48 (95% confidence interval 1.21-1.83). Patients who simultaneously initiated the use of antisecretory drugs with CCBs could not be found. Therefore, antisecretory drugs have not been used to prevent the gastrointestinal diseases caused by CCBs. The results obtained in this study suggest that the risk of gastrointestinal disease could be increased by long-term treatment with CCBs for elderly patients.