FROM A PROSPECTIVE-STUDY OF CHRONIC COUGH - DIAGNOSTIC AND THERAPEUTIC ASPECTS IN OLDER ADULTS

Background: Cough is the most common complaint for which adults see a physician in the ambulatory setting in the United States. An anatomica l diagnostic protocol has been used since 1981 to evaluate patients wi th chronic cough. It has been shown to be effective in diagnosing the cause of cough and leading to specific treatment in a variety of adult populations but has never been evaluated specifically in a population of older adults. Objectives: To question whether the spectrum and fre quency of causes of chronic cough and the response to therapy would be different in older adults. Methods: Thirty patients at least 64 years of age with a history of cough lasting at least 3 weeks were prospect ively evaluated with a protocol designed to detect diseases that stimu late the afferent limb of the cough reflex. The final diagnosis of the cause of chronic cough required fulfillment of pretreatment criteria and having cough disappear with specific therapy. When more than one d isease fulfilled pretreatment diagnostic criteria, therapy was institu ted in the order that these were fulfilled. Probability statistics wer e used to describe the testing characteristics of individual component s of the diagnostic protocol in terms of sensitivity, specificity, pos itive predictive value, and negative predictive value as they applied to chronic cough. Results: Forty causes of chronic cough were identifi ed in all 30 patients. Postnasal drip syndrome, gastroesophageal reflu x disease, and asthma were the most common causes of chronic cough, ac counting for 85% of all causes found. Among patients with normal chest radiograph findings who were not cigarette smokers and not taking an angiotensin-converting enzyme inhibitor, postnasal drip syndrome, gast roesophageal reflux disease, and asthma accounted for 100% of all caus es found. Specific therapy was successful in eliminating chronic cough in 100% of the patients studied. Except for barium esophagography, al l laboratory tests for which information was available had sensitiviti es and negative predictive values of 100%. Conclusions: Postnasal drip syndrome, gastroesophageal reflux disease, and asthma accounted for 8 5% of all causes of chronic cough in older adults. Chronic cough cause d substantial physical and emotional morbidity among older patients. T he major value of performing objective testing in evaluating chronic c ough is its ability to rule out specific diseases as a diagnostic poss ibility. The following clinical profile consistently predicts patients with cough attributable to gastroesophageal reflux disease: the patie nt has cough that has been persistently troublesome for at least 3 wee ks; does not smoke cigarettes; does not take an angiotensin-converting enzyme inhibitor; does not have or has not responded to therapy for p ostnasal drip syndrome and asthma; and has normal or nearly normal fin dings and stable chest radiograph. The differences between what we obs erved regarding chronic cough in older adults and observations by ours elves and others regarding chronic cough in general are minor.