Background:
Monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) are plasma cell disorders known to occur more frequently in Black populations, particularly among African Americans. Despite Sub-Saharan Africa (SSA) being home to the largest Black population globally, epidemiological data on MGUS and MM across the region remain limited, fragmented, and under-represented in global estimates. This paucity of data hampers effective health planning, early detection strategies, and equitable allocation of diagnostic and therapeutic resources. Understanding the burden, survival outcomes, and clinical characteristics of MGUS and MM in SSA is therefore critical to addressing global inequities in plasma cell disorder care.

Methods:
We conducted a systematic review and meta-analysis of published studies reporting on MGUS and MM in SSA. Multiple electronic databases were searched for eligible studies conducted within SSA populations. Data were extracted on prevalence, regional distribution, survival outcomes, and key clinical complications, including HIV-associated MM, renal failure, anaemia, and hypercalcaemia. Random-effects meta-analyses were used to estimate pooled prevalence and survival outcomes, accounting for between-study heterogeneity. Subgroup analyses were performed to explore regional variations and the modifying effect of HIV status on MM outcomes.

Results:
A total of 45 studies met the inclusion criteria, comprising eight studies on MGUS and 37 studies on MM. The pooled prevalence of MGUS in SSA was 3.1% (95% CI: 0.8–12.0%), while the pooled prevalence of MM was 7.8% (95% CI: 5.6–10.4%). Considerable regional variation was observed. MM burden was highest in Central Africa and lowest in West Africa, whereas MGUS prevalence was highest in Southern Africa. Survival outcomes were poor across the region. The pooled mean survival for MM was 34.7 months, with 1-year and 5-year overall survival rates of 46.0% and 20.7%, respectively. HIV infection significantly modified MM outcomes. The pooled prevalence of MM among people living with HIV was 7.2% (95% CI: 1.9–24.2%), and mean survival among HIV-positive MM patients was markedly shorter at 9.9 months, compared with 36.7 months among HIV-negative patients. Renal failure was a major complication, affecting 30.1% (95% CI: 23.5–37.6%) of MM patients at diagnosis, reflecting late presentation and limited access to early diagnostic services.

Conclusion:
MGUS and MM impose a substantial yet under-recognised burden in SSA, with survival outcomes that are markedly poorer than global averages. High rates of delayed diagnosis, limited diagnostic infrastructure, absence of routine screening for plasma cell disorders, and restricted access to modern anti-myeloma therapies likely contribute to these disparities. The pronounced impact of HIV on MM outcomes further underscores the need for integrated care pathways in high HIV-burden settings. Strengthening diagnostic capacity, improving early detection, and expanding access to effective treatment are urgently required to advance equity in myeloma care and reduce avoidable mortality across SSA.