Prognostic accuracy of time to sputum culture conversion in predicting cure in extensively drug-resistant tuberculosis patients: a multicentre retrospective observational study

Abstract

Background There was a lack of information about prognostic accuracy of time to sputum culture conversion (SCC) in forecasting cure among extensively drug-resistant tuberculosis (XDR-TB) patients. Therefore, this study evaluated the prognostic accuracy of SCC at various time points in forecasting cure among XDR-TB patients. Methods This retrospective observational study included 355 eligible pulmonary XDR-TB patients treated at 27 centers in Pakistan between 01-05-2010 and 30-06-2017. The baseline and follow-up information of patients from treatment initiation until the end of treatment were retrieved from electronic nominal recording and reporting system. Time to SCC was analyzed by Kaplan–Meier method, and differences between groups were compared through log-rank test. Predictors of time to SCC and cure were respectively evaluated by multivariate Cox proportional hazards and binary logistic regression analyses. A p-value < 0.05 was considered statistically significant. Results A total of 226 (63.6%) and 146 (41.1%) patients respectively achieved SCC and cure. Median time to SCC was significantly shorter in patients who achieved cure, 3 months (95% confidence interval [CI]: 2.47–3.53), than those who did not (median: 10 months, 95% CI: 5.24–14.76) (p-value < 0.001, Log-rank test). Patient’s age > 40 years (hazards ratio [HR] = 0.632, p-value = 0.004), baseline sputum grading of scanty, + 1 (HR = 0.511, p-value = 0.002), + 2, + 3 (HR = 0.523, p-value = 0.001) and use of high dose isoniazid (HR = 0.463, p-value = 0.004) were significantly associated with early SCC. Only SCC at 6 month of treatment had statistically significant association with cure (odds ratio = 15.603, p-value < 0.001). In predicting cure, the sensitivities of SCC at 2, 4 and 6 months were respectively 41.8% (95%CI: 33.7–50.2), 69.9% (95%CI: 61.7–77.2) and 84.9% (95%CI: 78.1–90.3), specificities were respectively, 82.8% (95%CI: 76.9–87.6), 74.6% (95%CI: 68.2–80.4) and 69.4% (95%CI: 62.6–75.5) and prognostic accuracies were respectively 65.9% (95%CI: 60.7–70.8), 72.7% (95%CI: 67.7–77.2) and 75.8% (95%CI: 71.0–80.1). Conclusion In forecasting cure, SCC at month 6 of treatment performed better than SCC at 2 and 4 months. However, it would be too long for clinicians to wait for 6 months to decide about the regimen efficacy. Therefore, with somewhat comparable prognostic accuracy to that SCC at 6 month, using SCC at 4 month of treatment as a prognostic marker in predicting cure among XDR-TB patients can decrease the clinicians waiting time to decide about the regimen efficacy.

Comparative effectiveness of individualized longer and standardized shorter regimens in the treatment of multidrug resistant tuberculosis in a high burden country

“…Time to SCC was analysed by Kaplan Meier method, and differences between groups were assessed using the log-rank test. Multivariate Cox Proportional Hazards and binary logistic regression analyses were respectively used to evaluate predictors of time to SCC and unsuccessful treatment outcomes (Abubakar et al, 2022). After checking for correlation, those factors which had a p-value of < 0.2 in univariate analysis were entered in multivariate analysis.…”

Treatment Outcome Monitoring by Using Sputum Conversion Rate of Tuberculosis Patients in Pkd Kinta, Malaysia

“…Tuberculosis positive sputum have 92.7 % (139) and Extra TB is 73 % (11). Number being studied in phase standardized daily treatment of the first 2 months TB was detected is 40.7 % i(61) and 59.3 % i(89) on standardized treatment phase twice a week (biweekly) after the intensive phase ends (18).…”

Frequency, management and impact of adverse events on treatment outcomes in patients with multidrug resistant tuberculosis in Balochistan, Pakistan

“…MDR-TB patients without resistance to any SLD were treated with amikacin (Am)/kanamycin (Km)/capreomycin (Cm) + Lfx + Eto + Cs + Z + vitamin-B 6 , while patients with resistance to any SLD had PAS added to the aforementioned regimen. Patients were given the maximum recommended doses per body weight ( Table 1 ) and treated for a minimum of 18 months after achieving sputum culture conversion (SCC) defined as ‘two successive negative sputum cultures taken at a one month interval following a baseline positive culture' (Abubakar, Ahmad, Atif, Ahmad, et al, 2022 ). Injectable SLD (Am/Km/Cm) was administered for at-least eight months, and a minimum of six months post SCC.…”