Table 2. Characteristics of the included studies in review.

Author	Study design	Methods	Location of study (City, Country)	Income settingsa	N	Subpops	% Female	Mean age	Intervention type	Theoretical framework	Retention definition
Agbonyitor et al. [32]	Qual	FGD	Amper, Fobur, Barkin Ladi, and Langtang, Nigeria	Middle	53	30 PLWH; 22 volunteer	PLWH: 80 %, volunteer: 82%	PLWH: 40.7, volunteer: 35.8	Home-based care	Thematic analysis	NR
Alamo et al. [41]	Mixed	In-depth interviews	Uganda	Low	394	347 patients; 47 CATTS	Patients: 71 %, CATTS: 63 %	Patients: 37(mdn), CATTS: 39 (mdn)	Task shifting to community health workers (CHW) & (CATTS)	Thematic analysis	Lost to follow-up
Assefa et al. [42]	Mixed	KII + FGD	Ethiopia	Low	84	72 KI;12 ART mentors	NR	NR	Complex	Self-generated framework	Continuous engagement of patients in care
Bezabhe et al. [33]	Qual	Semi-structured interview + FGD	Ethiopia	Low	58	24 PLWH, 15 nurses, 19 case managers	PLWH: 50 %, healthcare providers: 65 %	PLWH: 36, healthcare providers: 32	Case management	Grounded theory	Loss to follow-up
Busza et al. [34]	Qual	In-depth interview	Dar es Salaam, and Tanga region, Tanzania	Low	36	14 adolescents living with HIV, 10 caregivers, 12 home based care providers	Adolescents: 64%, caregivers: 90 %, HBC providers: 83 %	NR	Home-based care	NR	NR
Busza et al. [35]	Qual	Semi-structured	Harare, Zimbabwe	Low	20	15 primary caregivers,5 CBO	Primary caregiver: 80 %, CBO: 78 %	NR	Community-based intervention (home visits)	Skovdal et al. Conceptual framework	NR
Mallinson et al. [37]	Qual	In-depth interview	United States	High	76	None	46%	38.9	Outreach initiative program -focus on physician relationship	Grounded theory	NR
Miller et al. [38]	Qual	Face-to-face or telephone interview	South Africa	Middle	30	14 treatment defaulters;16 transfer patients	75 %; 42 %	31; 34	ARV treatment	NR	1 month late for the next scheduled consultation or meds pick up
Rajabiun et al. [39]	Qual	Semi-structured	United States	High	76	None	46%	38.9	Outreach intervention	Grounded theory	NR
Smillie et al. [40]	Qual		Semi-structured	Nairobi, Kenya	Middle	20	5 health care providers;15 patients living with HIV	73 %	29	mHealth	Theory of reasoned action and the technology acceptance model	NR
Decroo et al. [36]	Qual		FGD	Lesotho	Low	NR	NR	NR	NR	Community antiretroviral therapy groups (CAGs)	NR	NR

^aCountry income information is based on the World Bank category.

Qual qualitative study. Mixed mixed methods study including qualitative and quantitative methods. FGD focus group discussion. KII Key informant Interview. CATTS community antiretroviral therapy and tuberculosis treatment supporters. PLWH people living with HIV. NR none reported