Incidence of active tuberculosis among people living with HIV receiving long-term antiretroviral therapy in high TB/HIV burden settings in Thailand: implication for tuberculosis preventive therapy

Introduction

Among high tuberculosis (TB) and HIV burden countries in Asia, tuberculosis preventive therapy (TPT) in people living with HIV (PLWH) has been underutilized despite its proven benefits independent of antiretroviral therapy (ART). Therefore, we determined the incidence of active TB and mortality among 9179 adult PLWH who attended and received ART from 15 tertiary care hospitals across Thailand.

Methods

A retrospective study was conducted in 2018 using follow‐up data from 1999 to 2018. The primary endpoint was incident TB disease after ART initiation. Factors associated with TB incidence were analysed using competing risk regression. The Kaplan–Meier method was used to estimate mortality after ART initiation.

Results

During a median of 5.1 years of ART (IQR 2.2–9.5 years), 442 (4.8%) PLWH developed TB (TB/HIV), giving an overall incidence of 750 (95% CI 683–823) per 100,000 persons‐year of follow up (PYFU). In multivariate analysis, lower CD4 at ART initiation (≤100 cells/mm³, adjusted sub‐distribution hazard ratio [aSHR]: 2.08, 95% CI, 1.47–2.92; 101–200 cells/mm³, aSHR: 2.21, 95% CI, 1.54–3.16; 201–350 cells/mm³, aSHR: 1.59, 95% CI, 1.11–2.28 vs. >350 cells/mm³), male sex (aSHR: 1.40, 95% CI, 1.11–1.78), lower body weight (<50 kg, aSHR: 1.52, 95% CI, 1.17–1.95) and prior TB event (aSHR: 3.50, 95% CI, 2.72–4.52) were associated with TB incidence. PLWH with HIV RNA ≥50 copies/ml had 5–9 times higher risk of active TB disease higher than those with HIV RNA <50 copies/ml at the same CD4 level. The risk for developing TB was remarkably high during the initial period of ART (175,511 per 100,000 PYFU at<3 months) and was comparable to the general population after 10 years of ART (151 per 100,000 PYFU). TB/HIV had higher mortality (10% vs. 5%) and poorer HIV treatment outcomes: HIV RNA <50 copies/ml (63.8% vs. 82.8%), CD4 cells count (317 vs. 508 cells/mm³) at the most recent visit.

Conclusions

In this high TB burden country, TB incidence was remarkably high during the first few years after ART initiation and thereafter decreased significantly. Rapid ART initiation and appropriate TPT can be potential key interventions to tackle the TB epidemic and reduce mortality among PLWH in TB/HIV high burden settings.

Low-dose versus standard-dose ritonavir-boosted atazanavir in virologically suppressed Thai adults with HIV (LASA): a randomised, open-label, non-inferiority trial

BACKGROUND

Thai patients with HIV have higher exposure to HIV protease inhibitors than do white people and dose reduction might be possible. We compared the efficacy of low-dose with standard-dose ritonavir-boosted atazanavir in virologically suppressed Thai patients with HIV.

METHODS

In this randomised, open-label, non-inferiority trial, we recruited patients aged 18 years or older who were receiving ritonavir-boosted protease-inhibitor-based antiretroviral therapy (ART) with HIV plasma viral loads of less than 50 copies per mL, an alanine aminotransferase concentration of less than 200 IU/L, and a creatinine clearance of at least 60 mL/min from 14 hospitals in Thailand. We excluded patients who had active AIDS-defining disease or opportunistic infections, had a history of an HIV viral load of 1000 copies per mL or more after 24 weeks of any ritonavir-boosted protease-inhibitor-based ART, used concomitant medications that could interact with the study drugs, were pregnant or lactating, had illnesses that might change the effect of the study drugs, or had a history of sensitivity to the study drugs. A biostatistician at the study coordinating centre randomly allocated patients (1:1) to switch the protease inhibitor for oral atazanavir 200 mg and ritonavir 100 mg or for atazanavir 300 mg and ritonavir 100 mg once daily, both with two nucleoside or nucleotide reverse transcriptase inhibitors at recommended doses. Randomisation was done with a minimisation schedule, stratified by recruiting centre, use of tenofovir, and use of indinavir as a component of the preswitch regimen. The primary endpoint was the proportion of patients with viral loads of less than 200 copies per mL at week 48, and we followed up patients every 12 weeks. Treatments were open label, the non-inferiority margin was -10%, and all patients who received at least one dose of study medication were analysed. This trial is registered with ClinicalTrials.gov, number NCT01159223.

FINDINGS

Between July 6, 2011, and Dec 23, 2013, we randomly assigned 559 patients: 279 to receive atazanavir 200 mg and ritonavir 100 mg (low dose) and 280 to atazanavir 300 mg and ritonavir 100 mg (standard dose). At week 48, 265 (97·1%) of 273 in the low-dose group and 267 (96·4%) of 277 in the standard-dose group had viral loads of less than 200 copies per mL (difference 0·68; 95% CI -2·29 to 3·65). Seven (3%) of 273 in the low-dose group and 21 (8%) of 277 in the standard-dose group discontinued their assigned treatment (p=0·01). 46 (17%) of 273 participants in the low-dose group and 97 (35%) of 277 in the standard-dose group had total bilirubin grade 3 or higher toxicity (≥3·12 mg/dL; p<0·0001).

INTERPRETATION

A switch to low-dose atazanavir should be recommended for Thai patients with well controlled HIV viraemia while on regimens based on boosted protease inhibitors.

FUNDING

The National Health Security Office and Kirby Institute for Infection and Immunity in Society.

Resistance patterns selected by nevirapine vs. efavirenz in HIV-infected patients failing first-line antiretroviral treatment: a bayesian analysis

Background

WHO recommends starting therapy with a non-nucleoside reverse transcriptase inhibitor (NNRTI) and two nucleoside reverse transcriptase inhibitors (NRTIs), i.e. nevirapine or efavirenz, with lamivudine or emtricitabine, plus zidovudine or tenofovir. Few studies have compared resistance patterns induced by efavirenz and nevirapine in patients infected with the CRF01_AE Southeast Asian HIV-subtype. We compared patterns of NNRTI- and NRTI-associated mutations in Thai adults failing first-line nevirapine- and efavirenz -based combinations, using Bayesian statistics to optimize use of data.

Methods and Findings

In a treatment cohort of HIV-infected adults on NNRTI-based regimens, 119 experienced virologic failure (>500 copies/mL), with resistance mutations detected by consensus sequencing. Mutations were analyzed in relation to demographic, clinical, and laboratory variables at time of genotyping. The Geno2Pheno system was used to evaluate second-line drug options. Eighty-nine subjects were on nevirapine and 30 on efavirenz. The NRTI backbone consisted of lamivudine or emtricitabine plus either zidovudine (37), stavudine (65), or tenofovir (19). The K103N mutation was detected in 83% of patients on efavirenz vs. 28% on nevirapine, whereas Y181C was detected in 56% on nevirapine vs. 20% efavirenz. M184V was more common with nevirapine (87%) than efavirenz (63%). Nevirapine favored TAM-2 resistance pathways whereas efavirenz selected both TAM-2 and TAM-1 pathways. Emergence of TAM-2 mutations increased with the duration of virologic replication (OR 1.25–1.87 per month increment). In zidovudine-containing regimens, the overall risk of resistance across all drugs was lower with nevirapine than with efavirenz, whereas in tenofovir-containing regimen the opposite was true.

Conclusions

TAM-2 was the major NRTI resistance pathway for CRF01_AE, particularly with nevirapine; it appeared late after virological failure. In patients who failed, there appeared to be more second-line drug options when zidovudine was combined with nevirapine or tenofovir with efavirenz than with alternative combinations.

Epidemiology of Staphylococcus aureus infections and the prevalence of infection caused by community-acquired methicillin-resistant Staphylococcus aureus in hospitalized patients at Siriraj Hospital

BACKGROUND

The CA-MRSA infections have emerged in many parts of the world over the past decade. To our knowledge, the prevalence of CA-MRSA infections in Thai patients is unknown.

OBJECTIVE

To determine an epidemiology of Staphylococcus aureus (S. aureus) infections in hospitalized patients in Siriraj Hospital and the prevalence of infections caused by community-acquired methicillin-resistant S. aureus (CA-MRSA).

MATERIAL AND METHOD

The study was carried out at Siriraj Hospital from January to May 2005. The eligible patients were hospitalized patients whom S. aureus were isolated from their clinical specimens submitted to Department of Microbiology. S. aureus isolate was classified into infection or colonization. S. aureus infections were further classified into methicillin-resistant S. aureus (MRSA) or methicillin-sensitive S. aureus (MSSA) infections, and hospital-acquired (HA) or community-acquired (CA) infections. CA-MRSA infection is defined as infection caused by MRSA isolated from the patient within 72-hour of hospitalization and has no features of HA MRSA infections.

RESULTS

There were 669 S. aureus isolates from 448 patients. Two hundred and sixty two patients (58.5%) were MSSA whereas 186 (41.5%) were MRSA infections. CA-MRSA was found in three isolates (0.9% of total MRSA) from two patients.

CONCLUSION

The prevalence of CA-MRSA infections in hospitalized patients in Siriraj Hospital was uncommon and these patients could probably be HA MRSA infections.