Exploring linkages between drought and HIV treatment adherence in Africa: a systematic review

Climate change is directly and indirectly linked to human health, including through access to treatment and care. Our systematic review presents a systems understanding of the nexus between drought and antiretroviral therapy (ART) adherence in HIV-positive individuals in the African setting. Narrative synthesis of 111 studies retrieved from Web of Science, PubMed/MEDLINE, and PsycINFO suggests that livelihoods and economic conditions, comorbidities and ART regimens, human mobility, and psychobehavioural dispositions and support systems interact in complex ways in the drought–ART adherence nexus in Africa. Economic and livelihood-related challenges appear to impose the strongest impact on human interactions, actions, and systems that culminate in non-adherence. Indeed, the complex pathways identified by our systems approach emphasise the need for more integrated research approaches to understanding this phenomenon and developing interventions.

Determine the ecological and climatic conditions leading to and associated with Rift Valley fever and chikungunya mosquito borne disease outbreaks.

Rainfall variability, Drought
Chikungunya outbreaks were attuned to abnormally high temperatures and drought, especially in East Africa. The effects of these on livestock and human beings are obvious. Vaccinating livestock was crucial to reduce losses and illness, even for human beings. But where possible, migrating -even temporarily -may be an option too.

Droughts and precipitation
Final maize yield reduced by 1·7 percent and drought and high temperature-prone African contexts face declines in production yield due to drought conditions amongst others. 5 Lunde and Lindtjorn 2013. 51 Quantitative study: reconstructed cattle density and distribution over two-periods (1955-1960; 2000-05).
Unclear: Study data focused on national cattle holdings linked to spatial data with country level estimates represented in georeferenced map points Africa-wide Quantify and assess the effect of climate variability on national cattle holdings in Africa from 1961-2008

Temperature, Precipitation and conflicts
Incremental global warming has seen declines in cattle population as observed in Northern Somalia, Northern Kenya, around the Niger river, Mauritania, parts of South Africa, Mozambique, Namibia, and Madagascar. Although there are large variations, dry areas have seen more reductions than wetter areas, which saw an increase. 6 Bartzke et al 2018. 52 Quantitative study using rainfall data from 15 rain gauges from 2 timeframes Severe drought year = annual or seasonal rainfall below the estimated 10-year return level (Less than 0·1 Narok Town, Kenya Quantify trends and variation in rainfall in the Maasai Mara ecosystem in East Africa to grasp the implications for Severe Drought and increased flooding Severe Drought and increased flooding have effects on animal population dynamics, resource scarcity and possible migration patterns (1965-2015 and 1913-2015) in Kenya.
rainfall probability). Severe Flood years = annual rainfall above the 10-year extreme return level.
animal population and biodiversity dynamics. Analyse the relationship between long-term rainfall and cattle population dynamics. The impact of multiple droughts on calving rates and herds die-offs.

Rainfall variability, Drought
Greater reductions in calving rates during droughts implied reduced herd growth potential. Breeding females and immature animals were influenced to a much greater degree by inter-annual rainfall variability than were mature males. The data showed a downward spiral for the total cattle holdings over a 21-year period, with a decline of 54%. 8 Call et al 2019. 54 Quantitative study: Gridded climate-household survey linked data. n=120 communities, n=850 households, and n=2000 agricultural plots for the years 2003 and 2013.

Uganda
Explore the impact of climate anomalies on farmers' on and off-farm livelihood strategies.

Extreme climate events
Droughts decrease agricultural productivity in the short term and reduce individual livelihood diversification in the long term. Smallholder farmers cope with higher temperatures in the short term, but in the long run struggle to adapt to above-average temperatures, which lower agricultural productivity and reduce opportunities for diversification. 9 Hassan A G et al., 2019. 55 Qualitative design: FGDs with farmers and government expert officials from the Yobe state Ministry of Environment 2 FGDs focused on farmers (19) and government officials (6). The total study population was 25.
Nigeria: Yobe state To investigate socioeconomic impacts of drought in Yobe state, and to proffer mitigation recommendations for the state Drought Drought impacts were felt in reduced harvest, damaged crops, lost harvest, and livestock mortality. Some of the coping strategies local to farmers such as traditional grain loans (to be repaid at harvest without interest) and storage of excess from good harvest times were noted to have been rendered nonexistent/ineffective since drought decimated farmers to a point that they could not assist one another. 10 Hyland and Russ 2019. 56 Quantitative (cross-national) study spanning across 19 Sub-Saharan African countries. Combined household survey, Demographic Health Survey, and gridded climate data.
Analysis focused on 73 percent of women (emphasis on non-migrating women (n=76, 914)) who were living in rural areas.
Sub-Saharan Africa: Women living in rural areas in the countries studied.
Examine long-term impacts of drought exposure on women born in 19 Sub-Saharan African countries across 4 decades Drought, Average Monthly temperature Women exposed to extreme drought earlier on in their childhood, and raised in rural households, were (found to be significantly) less wealthy as Adults. They also had fewer years of formal education as well as reduced Adult Height. Finally, their offspring also tend to be born with low birth weights. 11 Kilimani et al., 2018. 57 Quantitative design: Computational Generalised Equilibrium modelling -Econometric approachfocused on the Uganda Applied The UgAGE database is made up of n=37 industries and commodities, including 25 within the broader agriculture sector, and the Uganda: Countrylevel analysis Investigate how a drought which initially affects agricultural productivity can ultimately affect an entire economy.

Drought and loss of production
Econometric analysis show that Drought causes GDP to decline because it directly lowers productivity across various agriculture industries, thereby reducing the level of agricultural output, General Equilibrium (UgAGE) theory and database.
data elaborates demand and supply of taxable water in the economy.
which then leads to a temporary shutdown of capital in downstream manufacturing industries; drought also impacted household consumption, causing it to decline. On the whole, drought shocks negatively affected real GDP, industry output, employment, the trade balance and household consumption. 12 Yiran, G. A. B. and L. C. Stringer, 2016. 58 Quantitative spatial, time-series analysis Unclear Ghana: The savannah ecosystem Understand the nature of hazards (their frequency, magnitude and duration) and how they cumulatively affect humans Temperature and windstorms were analysed from the observed weather data.
Impacts from each hazard varied spatiotemporally. Within the study period, more 70% of years recorded severe crop losses with greater impacts when droughts and floods occur in the same year, especially in low lying areas. The effects of crop losses were higher in districts with no/little irrigation 13 Mare, F., et al., 2018. 59 Quantitative study: Primary data from commercial livestock producers. Multi-staged and simple random sampling techniques used to select provinces and commercial livestock producers.
Additional data: Open-ended and surveys.
Study population (n=350) consists mainly of commercial livestock producers from 7 out of 9 provinces in South Africa Explores khat production as an adaptive strategy situated within a larger resilience strategy. Specifically, khat's potential for improving shortterm food and economic security, juxtaposed against its potential for increasing vulnerability through reduced health outcomes and natural resource degradation.
khat production, drought Khat was positively associated with food security. It was a resilience (adaptation) strategy against climatic and economic shocks since it provided farmers (and households) with income to cushion various shocks. However, because Khat is water intensive, there is reason for caution given the documented potential for poor health outcomes related to khat consumption and the heavy reliance on irrigation for intensive khat production, combined with the unregulated nature of water withdrawals in Ethiopia. Quantitative study using longitudinal data on rural households to assess impacts of rainfall patterns on agroincome Rainfall zones: 1 (n = 205); 2 (n= 425); 3 (n = 455); 4 (n =711); 5 (n= 882); 6 (n=196); 7 (n=347); 8 (n=355); 9 (n=283) Population growth, economic growth and the relative stability of the political regimes.
Climate variations did not significantly impact the level of regional conflict or the number of total displaced people (TDP); variations in refugee numbers were significantly related to climatic variations as well as political stability, population and economic growth. Also, long-term population growth, short-term negative economic growth and extreme political instability seem to be primarily linked to conflict. Determine the economic benefits with and without terraces, including gross and net profit values, returns on labour, water productivity and impacts on poverty.
Soil conservation through the terracing of farming areas The soil conservation strategy employed in the pilot areas had significant positive effects on the productivity of crops and the overall income of families and food security. It also reduced soil erosion. Women who are exposed to aboveaverage temperatures report lower ideal family size and reduced probability of desiring a first and additional child. Precipitation anomalies (drought or flood) during 12 months prior to the DHS survey was associated with a significant reduction in ideal family size But longer spells (about 60-months) of above average precipitation was associated with increases in the ideal family size. Generally, women were therefore found to significantly prefer to adjust their fertility downwards during times of unfavourable environmental conditions, particularly hot spells, while responses to precipitation vary over the short and longer run. Adverse Drug effects Co-usage of cART and Anti-seizure medication was associated with increased nausea and vomiting after 2 patients using and those not using Anti-Epilepsy medications concurrently (with ART), as well as to examine the Viral Load (VL) response of a subset of the participants after six months to observe short term and long-term drug adverse effect (impacts) in patients weeks. In relation to medication adherence in the long term (after 6 months), some participants had decreased medical adherence and often missed clinic visits, raising concerns about the long-term efficacy and tolerability of HIV and Epilepsy cotreatment on resource limited settings. Motivators of good adherence included disclosure of HIV-positive status to more than one-person, frequent adherence counselling, self-efficacy for adherence to ART, positive interactions between patients and healthcare providers; and using adherence partners. Barriers to adherence were forgetfulness, transportation costs to and from the clinic, time away from work and side-effects. Exploring suboptimal adherence to ART, elevated viral load, and factors associated with each of these outcomes among pregnant women already on ART when entering PMTCT services.

ART-Adherence
Marital status, unintended pregnancy After adjustment for age, suboptimal adherence was significantly more common among women who were not married/cohabiting and women who reported a higher level of concern about taking ART.

South Africa
Assess the impact of a community-based adherence support service on the outcomes of patients on Antiretroviral therapy (ART) A significantly higher proportion of patients with a community-based adherence supporter (also known as a patient advocate, PA) had viral load (VL) of less than 400 copies/ml at six months of treatment (70%, p0·001); a significantly higher proportion of patients with PAs (89%) attained a treatment pickup rate of over 95% (67%; p0·021 Age (youth aged 16-24 years), CACs, Among CAC patients, Loss to follow-up (LTFU) and viral rebound were twice as likely in youth (16-24 years old) compared with older patients, but no difference in the risk of LTFU or viral rebound was observed by sex. CAC participation was associated with a 67% reduction in the risk of LTFU compared with community health centre, and this association persisted when stratified by patient demographic and clinic characteristics. 108 Luque-Fernandez et al., 2013. 130 Quantitative Study population (n=2829) individuals were followed.

South Africa: Khayelitsha, Cape Town
Evaluate the effectiveness of adherence clubs compared to traditional clinic-based care in maintaining or improving longterm retention-in-care and virologic suppression Patients-led adherence clubs and service delivery, Virologic rebound Club participation was strongly associated with virologic suppression at study entry. At the end of the study, 97% of club patients remained in care compared with 85% of other patients. In adjusted analyses club participation reduced loss-to-care by 57% (hazard ratio [HR] 0·43, 95% CI = 0·21-0·91) and virologic rebound in patients who were initially suppressed by 67% (HR 0·33, 95% CI = 0·16-0·67).
109 Nakamanya et al., 2019. 131 Qualitative (cross-sectional) Study sample (n=50). The participants were selected from an initial 953 who had been on ART for six months or more.

Uganda Wakiso and Kalungu
Investigate the role of treatment supporters in sustaining adherence for people living with HIV on long-term ART Treatment supporters' importance at ART initiation and long term; Gender of treatment support (gender dynamics) Treatment supporters are important both at ART initiation and long term (mental health and coping support); females more than males were played more supportive roles; and Individuals without treatment supporters seemed to have more challenges than those with continued support. 110 Marconi et al., 2013. 132 Quantitative Individuals who are 18 years and above who were receiving more than 5 months of their first ART regimen. Sample size= 158 cases and 300 controls (458 total) Depression; ART adherence; increased rates of broad psychopathology in Nigeria; ART Selfreport (1-month selfreport adherence vs not 1-week self-report (long-term vs shortterm adherence selfreport)) Within the Participants in Psychiatric group analysis, there was no statistically significant association between the participants' number of mood diagnoses or suicidality symptoms, and their reported number of missed doses in the past week or month; But the odds of having depression were three times higher in participants who were nonadherent in the preceding month, compared to those who were completely adherent (controlling for age, gender, marital status, education, class of occupation, duration of ART use and current CD4 count)

Migration (14)
Travel away from home (

Systems diagram linking drought and ART non-adherence in Africa
This systems diagram demonstrates the complex interlinkages between drought and ART non-adherence moderated by different factors. The colour codes represent different themes (green=Livelihoods and Economic conditions; grey=social support and psycho-behavioural disposition; light blue=Physical health constraints and ART regimens; orange=human mobility). The numbers represent the number of articles referencing a particular factor in this system.

Section/topic # Checklist item Reported on page #
Risk of bias across studies 15 Specify any assessment of risk of bias that may affect the cumulative evidence (e.g., publication bias, selective reporting within studies).

Study selection
17 Give numbers of studies screened, assessed for eligibility, and included in the review, with reasons for exclusions at each stage, ideally with a flow diagram.

(Figure)
Study characteristics 18 For each study, present characteristics for which data were extracted (e.g., study size, PICOS, follow-up period) and provide the citations.

2-3, Appendix IV (pp 4-32)
Risk of bias within studies 19 Present data on risk of bias of each study and, if available, any outcome level assessment (see item 12).

3, Appendix V-VI (pp 33-34)
Results of individual studies 20 For all outcomes considered (benefits or harms), present, for each study: (a) simple summary data for each intervention group (b) effect estimates and confidence intervals, ideally with a forest plot.

n/a
Synthesis of results 21 Present results of each meta-analysis done, including confidence intervals and measures of consistency.

3-7
Risk of bias across studies 22 Present results of any assessment of risk of bias across studies (see Item 15).
n/a DISCUSSION Summary of evidence 24 Summarize the main findings including the strength of evidence for each main outcome; consider their relevance to key groups (e.g., healthcare providers, users, and policy makers).

7-8
Limitations 25 Discuss limitations at study and outcome level (e.g., risk of bias), and at review-level (e.g., incomplete retrieval of identified research, reporting bias).

8
Conclusions 26 Provide a general interpretation of the results in the context of other evidence, and implications for future research.

7-8 FUNDING
Funding 27 Describe sources of funding for the systematic review and other support (e.g., supply of data); role of funders for the systematic review. For more information, visit: www.prisma-statement.org.
Page numbers refer to the PDF version of the paper.