Pharmaceutical Research

Decision model can help doctors identify which patients will develop a cough from taking an ACE inhibitor

Angiotensin-converting enzyme (ACE) inhibitors improve the prognosis of patients with hypertension, heart attack, congestive heart failure, and renal diseases. The 5 to 25 percent of users of ACE inhibitors who develop a dry cough are often prescribed less effective and more costly angiotensin II receptor blockers (ARBs). However, switching from an ACE inhibitor to an ARB often entails additional clinic visits and medication costs. A new decision model can help doctors predict the likelihood that a given patient will develop a cough within 6 months from taking an ACE inhibitor.

In a study that was supported in part by the Agency for Healthcare Research and Quality (HS11169), researchers from Brigham and Women's Hospital, Harvard University, and Japan's Kyoto University developed the model by retrospectively collecting clinical data on 1,125 patients who were prescribed an ACE inhibitor for the first time and identifying correlates of ACE inhibitor-induced cough. They validated the resulting model with 567 patients. The 1,692 patients were followed for at least 180 days after an initial prescription for an ACE inhibitor to identify those who developed a cough within that period.

In the total group, 12 percent of patients developed ACE-inhibitor-induced cough. Independent predictors of cough were older age, female sex, non-black race (with East Asians having the highest risk), no history of previous ACE-inhibitor use, and a history of cough due to another ACE-inhibitor. These factors were used to develop a model stratifying patients into four risk groups: low-risk, average-risk, intermediate-risk, and high-risk. In the validation set, 4 percent, 14 percent, 20 percent, and 60 percent of patients in these four groups developed a cough, respectively.

The researchers conclude that use of this decision rule allows rapid estimation of risk of cough due to an ACE inhibitor within 6 months. This information may be valuable in clinical decisionmaking regarding starting ACE inhibitors and considering withdrawal of an ACE inhibitor or the need for a workup for cough.

See "Development and validation of a clinical prediction rule of angiotensin-converting enzyme inhibitor-induced cough," by Takeshi Morimoto, M.D., M.P.H., Tejal K. Gandhi, M.D., M.P.H., Julie M. Fiskio, B.S., and others, in the June 2004 Journal of General Internal Medicine 19, pp. 684-691.

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