Factors associated with attrition in patients with breast cancer: a retrospective study.

BACKGROUND: Attrition in follow up is a key limitation of longitudinal studies, especially in cancer patients in developing countries. We did a retrospective analysis of possible factors that resulted in attrition of patients with breast cancer during follow up. METHODS: This study is a comparison between patients who came for a follow up regularly to our clinic with those who did not but could be contacted on phone or by post. A computerized grouped database was constructed with the following parameters: age, religious community, other co-morbid conditions if present, distance from place of residence to our city, residence in city/ village, initial stage of the disease, type of treatment and disease relapse or death. RESULTS: Using binary logistic regression, disease relapse was found to be the most important cause of non-compliance. The odds ratio for irregularity or loss to follow up of patients with disease relapse was 2.53 (95% CI: 1.17-5.46; p = 0.02) for patients who were alive with disease relapse and 6.1 8 (95% CI: 3.47-11.02; p < 0.001) for patients who had died due to the disease compared with those who were alive and free of disease. The age and place of residence in a village were other significant factors. The odds of attrition due to age were 1.03 (95% CI: 1.01-1.05; p = 0.04) for each year of increase in age and that of residence in a village was 1.85 (95% CI: 1.02-3.36; p = 0.04). CONCLUSION: Age, disease relapse and residing in a village are important causes of attrition during follow up of patients with breast cancer in India.