Therapeutic-diagnostic evaluation of chronic cough amongst adults: causes, symptoms and management at the primary care level, Malaysia

BACKGROUND: Patients presenting with chronic cough pose a common diagnostic dilemma during routine consultations at public primary care clinics in Malaysia. To date, there has been little attempt at designing a standardized model or algorithm to facilitate an accurate diagnosis of chronic cough. This study proposes a clinical method to detect the causes of chronic cough in a primary care setting in Malaysia.
MATERIALS AND METHODS: A total of 117 patients aged above 18 at an urban primary care clinic were tracked over a span of 5 months to diagnose the cause of chronic cough. A therapeutic-diagnostic method was employed to help identify the causes of chronic cough. Subsequently, the demographic details of patients, the prevalence of the different causes of chronic cough and the relationship between history and diagnosis were analyzed statistically.
RESULTS: Chronic cough had a slightly higher male preponderance (51.3% vs. 48.7%). Patients within the 'above 60' age category had the highest frequency of chronic cough. The most common cause of chronic cough was post-infectious cough (n = 42, 35.9%), followed closely by angiotensin-converting enzyme-inhibitor related cough (n = 14, 12%). Majority of patients had the symptom of phlegm production (n = 41, 54%). 33 patients (29.2%) had recent upper respiratory tract infection (<2 weeks ago) prior to the diagnosis of chronic cough. There were poor association between symptoms and the various entities comprising chronic cough. The exceptions were the following associations: (1) Bronchial asthma and itchiness of throat (P = 0021), (2) gastroesophageal reflux disease and heartburn (P < 0.001), (3) upper airway cough syndrome and running nose (P = 0.016) and (4) pulmonary tuberculosis and absence of weight loss (P = 0.004).
CONCLUSION: This study demonstrates that the effectiveness of a therapeutic-diagnostic technique in the diagnosis of chronic cough. Consistent with previous studies, there was poor association between most symptoms and the causes of chronic cough. A study involving a larger primary care population is required to confirm the findings found in this analysis.
KEYWORDS: Angiotensin-converting enzyme-I related cough; chronic cough; post-infectious cough; primary care; therapeutic-diagnostic evaluation