Contact evaluation and isoniazid preventive therapy among close and household contacts of tuberculosis patients in Lima, Peru: an analysis of routine data

Abstract

Objective Contacts of pulmonary tuberculosis (TB) cases are at high risk of TB infection and progression to disease. Close and household contacts and those <5 years old have the highest risk. Isoniazid preventive therapy (IPT) can largely prevent TB disease among infected individuals. International and Peruvian recommendations include TB contact investigation and IPT prescription to eligible contacts. We conducted a study in Lima, Peru, to determine the number of close and household contacts who were evaluated, started on IPT, and who completed it, and the factors associated to compliance with national guidelines. Methods We conducted a longitudinal retrospective study including all TB cases diagnosed between January 2015 and July 2016 in 13 health facilities in south Lima. Treatment cards, TB registers and clinical files were reviewed and data on index cases (sex, age, smear status, TB treatment outcome), contact investigation (sex, age, kinship to the index case, evaluations at month 0, 2 and 6) and health facility (number of TB cases notified per year, proportion of TB cases with treatment success) were extracted. We tabulated frequencies of contact evaluation by contact and index case characteristics. To investigate determinants of IPT initiation and completion, we used generalised linear mixed models. Results A total of 2323 contacts were reported by 662 index cases; the median number of contacts per case was four (IQR, 2–5). Evaluation at month 0 was completed by 99.2% (255/257) of contacts <5 and 98.1% (558/569) of contacts aged 5–19 years. Of 191 eligible contacts <5 years old, 70.2% (134) started IPT and 31.4% (42) completed it. Of 395 contacts 5–19 years old, 36.7% (145) started IPT and 32.4% (47) completed it. Factors associated to not starting IPT among contacts <5 years old were being a second‐degree relative to the index case (OR 6.6 95CI% 2.6–16.5), not having received a tuberculin skin test (TST) (OR 3.9 95%CI 1.4–10.8), being contact of a smear‐negative index case (OR 5.5 95%CI 2.0–15.1) and attending a low‐caseload health facility (OR 2.8 95%CI 1.3–6.2). Factors associated to not starting IPT among 5–19 year‐olds were age (OR 13.7 95%CI 5.9–32.0 for 16‐19 vs. 5–7 years old), being a second‐degree relative (OR 3.0 95%CI 1.6–5.6), not having received a TST (OR 5.4, 95%CI 2.5–11.8), being contact of a male index case (OR 2.1 95CI% 1.2–3.5), with smear‐negative TB (OR 1.9 95%CI 1.0–3.6), and attending a high‐caseload health facility (OR 2.1 95%CI 1.2–3.6). Factors associated to not completing IPT, among contacts who started, were not having received a TST (OR 3.4 95%CI 1.5–7.9 for <5 year‐olds, and OR 4.3 95%CI 1.7–10.8 for those 5–19 years old), being contact of an index case with TB treatment outcome other than success (OR 9.3 95%CI 2.6–33.8 for <5 year‐olds and OR 15.3 95%CI 1.9–125.8 for those 5–19 years old), and, only for those 5–19 years old, attending a health facility with high caseload (OR 3.2 95%CI 1.4–7.7) and a health facility with low proportion of TB cases with treatment succ...

Closing delivery gaps in the treatment of tuberculosis infection: Lessons from implementation research in Peru

“…While completion of the TB preventive cascade was only 18–34% among contacts and poorer among health care workers and people in congregate settings, these results are consistent with what programs in high-income countries often achieve; a systematic review of the TB preventive care cascade, in which the majority of studies came from high-income countries, estimated cascade completion to be 19% globally [ 23 ]. Moreover, as a negligible number of adults in Peru currently access preventive treatment [ 18 ], this study represents an important initial step to expanding access. We found that TB infection testing and treatment were acceptable in this population, with >90% of participants completing testing and initiating treatment if prescribed.…”

“…National TB guidelines [ 17 ] mandate preventive treatment with 6 months of isoniazid following rule-out of active TB disease for five groups: (a) children <5 years old who are contacts of patients with pulmonary TB, regardless of TST result; (b) people 5–19 years who are contacts of pulmonary patients with pulmonary TB and who have TST results of ≥10 mm induration; (c) people living with HIV, regardless of TST result; (d) health care workers with TST conversion; and (e) people with certain medical comorbidities, based on clinician judgement. The guidelines neither mandate nor prohibit preventive treatment for adult close contacts, but few are typically treated [ 18 ]. As isoniazid is the only preventive treatment medication used in this setting, the guidelines recommend that preventive treatment not be given to contacts of patients with drug-resistant TB because of presumed resistant infection, although new guidance to use levofloxacin is currently under consideration.…”

Incident Tuberculosis Diagnoses in Children at High Risk for Disease

“…Appropriately, providers may hold off on IPT if there is uncertainty about whether a child has TB. In our cohort, this was evidenced by a lower frequency of IPT among these children relative to a programmatic cohort in Lima, Peru, from the same time period [ 17 ].…”

Toward patient-centered tuberculosis preventive treatment: preferences for regimens and formulations in Lima, Peru

“…14,15 Moreover, many household contacts of patients with TB are not aware of their increased risk of developing TB, 15 and use of preventive treatment for contacts is suboptimal. [16][17][18] Preventive treatment in Peru is recommended for contacts of patients with drugsusceptible pulmonary TB. 19 It is explicitly recommended for contacts who are <5 years old or who are 5-19 years old with a positive TST result, and doctors can use their discretion for others who are at high risk.…”