Enhancing therapy monitoring and effectiveness for HIV patients in China's border regions through a healthcare consortium: an interrupted time series analysis.

BACKGROUND: HIV/AIDS remains a significant global health challenge, particularly in economically disadvantaged and underserved regions. Inequities in access to timely HIV diagnosis, treatment, and prevention services hinder progress in controlling the epidemic. Border counties of southwestern China face additional structural barriers including cross-border population movement, fragmented service delivery across mountainous terrain, and limited specialised workforce. OBJECTIVE: This study evaluates the contribution of a regional healthcare consortium model, established in May 2020 in M City, Yunnan Province, to improving therapy monitoring and effectiveness for people living with HIV. METHODS: We conducted a retrospective single-site study using monthly aggregate programme data from January 2019 to July 2024. Indicators followed the WHO Consolidated Strategic Information Guidelines and the UNAIDS 95-95-95 framework, and included viral load (VL) testing rates, antiretroviral therapy (ART) coverage, and trimethoprim-sulfamethoxazole (SMZ) prophylaxis. Pre-intervention covered January 2019 to May 2020 and post-intervention covered June 2020 to July 2024. Descriptive statistics were complemented by an Interrupted Time Series (ITS) segmented regression analysis with Newey-West standard errors. Normality was tested with the Shapiro-Wilk statistic and non-parametric tests were used where appropriate. Multiple testing was controlled with the Benjamini-Hochberg false discovery rate procedure. Sensitivity analyses excluded peak COVID-19 disruption months and adjusted for the 2022 national HIV treatment guideline update. The study followed STROBE reporting standards. FINDINGS: Following implementation of the consortium, the monthly number of newly enrolled ART patients increased by 69.8%, the VL test completion rate by 20.6% points (from 74.3% to 93.6%), the ART coverage rate by 7.2% points (from 85.9% to 92.6%), and the SMZ usage rate by 7.6% points (from 91.4% to 98.9%). ITS analysis showed sustained post-reform improvements in ART coverage rate (β1 + β3 = 0.162% points per month, P < 0.001 after FDR adjustment), in newly enrolled patients (β1 + β3 = 1.169 patients per month, P < 0.001), and a small but significant gain in the overall VL testing rate (β1 + β3 = 0.015% points per month, P < 0.05). Findings were robust to the exclusion of COVID-19 lockdown months and to adjustment for the 2022 guideline update. INTERPRETATION: In this single border city, the regional consortium was associated with substantial improvements in HIV care continuum indicators. The findings should be interpreted as evidence of the consortium's contribution rather than sole attribution, given the absence of a contemporaneous control. The model offers a candidate framework for HIV care integration in resource-constrained border counties of southwestern China and other comparable settings, although external validation through multi-site or controlled designs is required before broader generalisation.