Lost to follow up from tuberculosis treatment in an urban informal settlement (Kibera), Nairobi, Kenya: what are the rates and determinants?

Patients lost to follow up (LTFU) from treatment are a major concern for tuberculosis (TB) programmes. It is even more challenging in programmes in urban informal settlements (slums) with large, highly mobile, impoverished populations. Kibera, on the outskirts of Nairobi, Kenya is such a community with an estimated population of 500 000 to 700 000. Médecins Sans Frontières (MSF), in collaboration with the Kenyan Ministry of Public Health and Sanitation (MPHS), operate three clinics providing integrated TB, HIV and primary health care. We undertook a retrospective study between July 2006 and December 2008 to determine the rate of LTFU from the TB programme in Kibera and to assess associated clinical and socio-demographic factors. Thanks to an innovative 'Defaulter Tracing Programme', patients who missed their appointments were routinely traced and encouraged to return for treatment. Where possible, reasons for missed appointments were recorded. LTFU occurred in 146 (13%) of the 1094 patients registered, with male gender, no salaried employment, lack of family support and positive TB smear at diagnosis found to be significant associations (P value ≤ 0.05). The most commonly cited reasons for LTFU were relocation from Kibera to 'up-country' rural homes and work commitments.