Associations Between Laser Treatment Utilization, Regional Access, and Vision-Threatening Diabetic Retinopathy in Northwest Tanzania: A Retrospective Study

Background The influence of proximity to laser treatment centers on adherence and visual outcomes in patients with vision-threatening diabetic retinopathy (VTDR) in low-resource settings is not well known. This study evaluated adherence to initial laser treatment referral and best-corrected visual acuity (BCVA) at the time of referral, before and after the installation of a regional ophthalmic laser in northwest Tanzania (TZ). Materials and methods This was a retrospective cohort study conducted at a single tertiary care institution in northwest TZ. The study included adults with diabetes mellitus (DM) who were diagnosed with VTDR by ophthalmologists at Bugando Medical Centre in Mwanza, TZ, and referred for initial laser treatment between March 1, 2017, and May 1, 2019. Data were collected on patient demographics, VTDR classification (severe non-proliferative diabetic retinopathy, proliferative diabetic retinopathy, and/or clinically significant macular edema), BCVA at the time of referral, and referral adherence. Patients were categorized into two groups based on the location of available laser treatment centers at the time of their referral. The off-site group included patients referred to laser centers located out of the region before treatment became available locally. The on-site group included patients referred for laser treatment within the region after BMC began providing laser therapy for VTDR. Data from the off-site group was compared with data from the on-site group. Results A total of 68 patients were included, 32 referred off-site and 36 on-site. Referral for laser treatment on-site was associated with a greater rate of adherence compared to off-site (32/36 (89%) vs 21/32 (66%), <i>P</i> = 0.021). Greater adherence to on-site referrals was independent of sex (<i>P</i> = 0.024). The proportion of patients with at least moderate vision impairment (BCVA worse than 6/18) in the eye referred for laser was significantly higher among those referred off-site compared to on-site (23/32 (72%) vs 15/36 (42%), <i>P</i> = 0.012). Conclusions Greater adherence to initial laser treatment referral and better BCVA at the time of referral, providing a better baseline visual acuity to preserve, were observed when laser treatment was available on-site (within region) compared to off-site (out of region). These findings suggest that a systematic approach to improving regional access to laser treatment for adults with VTDR in TZ who must currently travel long distances for care could help delay or prevent blindness due to VTDR. These results have broad implications for other low-resource settings; further study is recommended.