Estimating the effect of pretreatment loss to follow up on TB associated mortality at public health facilities in Uganda

Abstract

Introduction Tuberculosis (TB) mortality estimates derived only from cohorts of patients initiated on TB treatment do not consider outcomes of patients with pretreatment loss to follow-up (LFU). We aimed to assess the effect of pretreatment LFU on TB-associated mortality in the six months following TB diagnosis at public health facilities in Uganda. Methods At ten public health facilities, we retrospectively reviewed treatment data for all patients with a positive Xpert®MTB/RIF test result from January to June 2018. Pretreatment LFU was defined as not initiating TB treatment within two weeks of a positive test. We traced patients with pretreatment LFU to ascertain their vital status. We performed Kaplan Meier survival analysis to compare the cumulative incidence of mortality, six months after diagnosis among patients who did and did not experience pretreatment LFU. We also determined the health facility level estimates of TB associated mortality before and after incorporating deaths prior to treatment initiation among patients who experienced pretreatment LFU. Results Of 510 patients with positive test, 100 (19.6%) experienced pretreatment LFU. Of these, we ascertained the vital status of 49 patients. In the six months following TB diagnosis, mortality was higher among patients who experienced pretreatment LFU 48.1/1000py vs 22.9/1000py. Hazard ratio [HR] 3.18, 95% confidence interval [CI] (1.61–6.30). After incorporating deaths prior to treatment initation among patients who experienced pretreatment LFU, health facility level estimates of TB associated mortality increased from 8.4% (95% CI 6.1%-11.6%) to 10.2% (95% CI 7.7%-13.4%). Conclusion Patients with confirmed TB who experience pretreatment LFU have high mortality within the first six months. Efforts should be made to prioritise linkage to treatment for this group of patients. Deaths that occur prior to treatment initation should be included when reporting TB mortality in order to more accurately reflect the health impact of TB.

Mortality and associated factors among adult patients on tuberculosis treatment in Tanzania: A retrospective cohort study

“…Correspondingly, TB patients receiving service at the hospital level had an increased hazard of death compared to those accessing service at the dispensaries. This was consistent with the study conducted in Spain [41] and Uganda [42] . A retrospective study conducted in Zimbabwe acknowledged that accessing treatment from a higher-level health facility reduced the risk of mortality among TB patients [7] .…”

Early mortality in tuberculosis patients initially lost to follow up following diagnosis in provincial hospitals and primary health care facilities in Western Cape, South Africa

“…Our estimate of 13 (IQR: 5–42) days to death from diagnosis among ILTFU TB patients is shorter than previous work which reported median time from diagnosis to death of 3.5 weeks [ 3 ] and 22 days [ 7 ]. This may be related to our focus on ILTFU regardless of treatment status or ascertaining more mortality in a much larger population of ILTFU patients.…”

“…In recent work, the proportions of pre-treatment loss to follow up amongst TB patients were similar (~20%) in Uganda [ 7 ], South Africa [ 8 ], Zimbabwe [ 9 ], and India [ 10 ] but the estimates of mortality differed. In South Africa, 2% died before starting treatment but mortality was not ascertained for the group who were lost to follow up before treatment [ 8 ].…”

“…In South Africa, 2% died before starting treatment but mortality was not ascertained for the group who were lost to follow up before treatment [ 8 ]. In Uganda, 22.4% of pre-treatment loss to follow up TB patients died, but mortality was only ascertained in 49 out of 100 patients with a positive Xpert results who were not initiated on TB treatment within two weeks of diagnosis [ 7 ]. In Zimbabwe 49.6% (252/508) of the pre-treatment loss to follow up TB patients died between 2012–2016 [ 9 ].…”

“…We were also not restricted to matching within TB treatment registers and were able to track attendance at PHC facilities or admissions at TB hospitals across the province. Previous studies based on paper-based treatment registers [ 7 – 10 ] were not able to track patients who returned to care after an initial test and may have over-estimated ILTFU. By using the electronic sources with a unique identifier, we were able to identify patients who returned for repeat testing and accessed treatment at any public facility in the Western Cape Province.…”