Establishing a cohort in a developing country: Experiences of the diabetes-tuberculosis treatment outcome cohort study.
BACKGROUND
Prospective cohort studies are instrumental in generating valid scientific evidence based on identifying temporal associations between cause and effect. Researchers in a developing country like Pakistan seldom undertake cohort studies hence little is known about the challenges encountered while conducting them. We describe the retention rates among tuberculosis patients with and without diabetes, look at factors associated with loss to follow up among the cohort and assess operational factors that contributed to retention of cohort.


METHODS
A prospective cohort study was initiated in October 2013 at the Gulab Devi Chest Hospital, Lahore, Pakistan. We recruited 614 new adult cases of pulmonary tuberculosis, whose diabetic status was ascertained by conducting random and fasting blood glucose tests. The cohort was followed up at the 2nd, 5th and 6th month while on anti-tuberculosis therapy (ATT) and 6months after ATT completion to determine treatment outcomes among the two groups i.e. patients with diabetes and patients without diabetes.


RESULTS
The overall retention rate was 81.9% (n=503), with 82.3% (93/113) among patients with diabetes and 81.8% (410/501) among patients without diabetes (p=0.91). Age (p=0.001), area of residence (p=0.029), marital status (p=0.001), educational qualification (p=<0.001) and smoking (p=0.026) were significantly associated with loss to follow up. Respondents were lost to follow up due to inability of research team to contact them as either contact numbers provided were incorrect or switched off (44/111, 39.6%).


CONCLUSION
We were able to retain 81.9% of PTB patients in the diabetes tuberculosis treatment outcome (DITTO) study for 12months. Retention rates among people with and without diabetes were similar. Older age, rural residence, illiteracy and smoking were associated with loss to follow up. The study employed gender matched data collectors, had a 24-h helpline for patients and sent follow up reminders through telephone calls rather than short messaging service, which might have contributed to retention of cohort.
['Mukhtar|Fatima|F|', 'Butt|Zahid A|ZA|']
D000293:Adolescent D000328:Adult D000368:Aged D000369:Aged, 80 and over D015331:Cohort Studies D015897:Comorbidity D003906:Developing Countries D003920:Diabetes Mellitus D005260:Female D005500:Follow-Up Studies D006801:Humans D008297:Male D008875:Middle Aged D010154:Pakistan D011446:Prospective Studies D016896:Treatment Outcome D014397:Tuberculosis, Pulmonary D055815:Young Adult
Cohort study Pakistan Tuberculosis Diabetes