Dataset Information

APOL1 risk alleles among individuals with CKD in Northern Tanzania: A pilot study.

ABSTRACT: Introduction: In sub-Saharan Africa, approximately 100 million people have CKD, yet genetic risk factors are not well-understood. Despite the potential importance of understanding APOL1 risk allele status among individuals with CKD, little genetic research has been conducted. Therefore, we conducted a pilot study evaluating the feasibility of and willingness to participate in genetic research on kidney disease, and we estimated APOL1 risk allele frequencies among individuals with CKD.

Methods: In 2014, we conducted a community-based field study evaluating CKD epidemiology in northern Tanzania. We assessed for CKD using urine albumin and serum creatinine to estimate GFR. We invited participants with CKD to enroll in an additional genetic study. We obtained dried-blood spots on filter cards, from which we extracted DNA using sterile punch biopsies. We genotyped for two single nucleotide polymorphisms (SNPs) defining the APOL1 G1 risk allele and an insertion/deletion polymorphism defining the G2 risk allele. Genotyping was performed in duplicate.

Results: We enrolled 481 participant, 57 (12%) of whom had CKD. Among these, enrollment for genotyping was high (n = 48; 84%). We extracted a median of 19.4 ng of DNA from each dried-blood spot sample, and we genotyped the two APOL1 G1 SNPs and the APOL1 G2 polymorphism. Genotyping quality was high, with all duplicated samples showing perfect concordance. The frequency of APOL1 risk variants ranged from 7.0% to 11.0%, which was similar to previously-reported frequencies from the general population of northern Tanzania (p>0.2).

Discussion: In individuals with CKD from northern Tanzania, we demonstrated feasibility of genotyping APOL1 risk alleles. We successfully genotyped three risk variants from DNA extracted from filter cards, and we demonstrated a high enrollment for participation. In this population, more extensive genetic studies of kidney disease may be well-received and will be feasible.

SUBMITTER: Stanifer JW

PROVIDER: S-EPMC5521837 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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APOL1 risk alleles among individuals with CKD in Northern Tanzania: A pilot study.

Stanifer John W JW Karia Francis F Maro Venance V Kilonzo Kajiru K Qin Xuejun X Patel Uptal D UD Hauser Elizabeth R ER

PloS one 20170721 7

<h4>Introduction</h4>In sub-Saharan Africa, approximately 100 million people have CKD, yet genetic risk factors are not well-understood. Despite the potential importance of understanding APOL1 risk allele status among individuals with CKD, little genetic research has been conducted. Therefore, we conducted a pilot study evaluating the feasibility of and willingness to participate in genetic research on kidney disease, and we estimated APOL1 risk allele frequencies among individuals with CKD.<h4> ...[more]

PMID: 28732083

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Project description:Background and objectivesCommon apolipoprotein L1 (APOL1) variants are associated with increased risk of progressive CKD; however, not all individuals with high-risk APOL1 variants experience CKD progression. Identification of factors contributing to heterogeneity has important scientific and clinical implications.Design, setting, participants, & measurementsUsing multivariable Cox models, we analyzed data from 693 participants in the African American Study of Kidney Disease and Hypertension to identify factors that modify the association between APOL1 genotypes and CKD progression (doubling of serum creatinine or incident ESRD).ResultsParticipant mean age was 54 years old, median GFR was 49 ml/min per 1.73 m(2), and 23% had the APOL1 high-risk genotype (two copies of the high-risk allele). Over a mean follow-up of 7.8 years, 288 (42%) participants experienced CKD progression. As previously reported, the high-risk genotype was associated with higher risk of CKD progression compared with the low-risk genotype (hazard ratio [HR], 1.88; 95% confidence interval [95% CI], 1.46 to 2.41). Although we found some suggestion that obesity (HR, 1.48; 95% CI, 1.05 to 2.08 and HR, 2.44; 95% CI, 1.66 to 3.57 for body mass index ≥ 30 versus <30 kg/m(2); P interaction =0.04) and increased urinary excretion of urea nitrogen (HR, 1.43; 95% CI, 0.98 to 2.09 versus HR, 2.33; 95% CI, 1.65 to 3.30 for urine urea nitrogen ≥ 8 versus <8 g/d; P interaction =0.04) were associated with lower APOL1-associated risk for CKD progression, these findings were not robust in sensitivity analyses with alternative cut points. No other sociodemographic (e.g., education and income), clinical (e.g., systolic BP and smoking), or laboratory (e.g., net endogenous acid production, urinary sodium and potassium excretions, 25-hydroxy vitamin D, intact parathyroid hormone, or fibroblast growth factor 23) variables modified the association between APOL1 and CKD progression (P interaction >0.05 for each).ConclusionsSociodemographic factors and common risk factors for CKD progression do not seem to alter APOL1-related CKD progression. Additional investigation is needed to identify nontraditional factors that may affect the association between APOL1 and progressive CKD.

Project description:Rationale & objectiveAPOL1 nephropathy risk alleles are associated with the development of chronic kidney disease (CKD) in African Americans. Although CKD is an established risk factor for mortality, associations of APOL1 risk alleles with mortality are uncertain.Study designProspective cohort.Settings & participants10,380 African American and 17,485 white American participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study.ExposuresAPOL1 nephropathy risk alleles.OutcomesAll-cause and cause-specific mortality.Analytical approachCox proportional hazards models were used to examine the association of APOL1 high-risk genotypes (2 risk alleles) versus APOL1 low-risk genotypes (0/1 risk allele) with all-cause and cause-specific mortality in African Americans and examine the risk for all-cause mortality in African Americans with high-risk genotypes versus African Americans with low-risk genotypes and white Americans.ResultsAPOL1 high-risk participants were younger and had a higher prevalence of albuminuria than low-risk participants. There was no statistically significant association of APOL1 high- versus low-risk genotypes with all-cause mortality in models adjusted for sociodemographic variables, comorbid conditions, and kidney function (HR, 0.88; 95% CI, 0.77-1.01). After further adjustment for genetic ancestry in a subset with available data, a statistically significant association emerged (HR, 0.81; 95% CI, 0.69-0.96). Associations differed by CKD status (Pinteraction=0.04), with African Americans with high-risk genotypes having lower risk for mortality than those with low-risk genotypes in fully adjusted models (HR, 0.78; 95% CI, 0.62-0.99) among those with CKD, but not those without CKD (HR, 0.84; 95% CI, 0.66-1.05). Compared with white Americans, African Americans with high-risk genotypes had a similar rate of mortality, whereas African Americans with low-risk genotypes had a higher rate of mortality (HR, 1.07; 95% CI, 1.00-1.14) in fully adjusted models.LimitationsLack of follow-up measures of kidney function.ConclusionsAfrican Americans with high-risk APOL1 genotypes had lower mortality than those with low-risk genotypes in multivariable-adjusted models including genetic ancestry.

Project description:Rationale and objectiveLatinx individuals are at a higher risk for kidney failure than non-Latinx White individuals; however, they are less likely to receive pre-kidney failure medical care. The objective of this study was to determine the feasibility and acceptability of a community health worker (CHW) intervention that facilitated access to medical care for Latinx individuals.Study designSingle-arm prospective study.Setting and participantsLatinx adults were found to have albuminuria or risk factors for kidney disease at community screening events in Austin, Texas.InterventionA 6-month CHW intervention that facilitated the following: (1) obtaining medical insurance; (2) medical care coordination with primary and nephrology care; (3) kidney disease education; and (4) connection with local resources to address health-related social needs.OutcomesRecruitment, retention, medical care linkage, and participant and CHW-reported satisfaction with the intervention.ResultsOf the 173 individuals who attended the 2 community screening events, 49 agreed to participate in the study, of whom, 51% were men with a mean ± standard deviation (SD) age of 45 ± 14 years, and all self-identified as Mexican or Chicano. The mean ± SD estimated glomerular filtration rate (eGFR) was 110 ± 21 mL/min/1.73 m2 and 41% of the participants reported a urine albumin-creatinine ratio of ≥30 mg/g. Among those enrolled, 28 of the 49 (57%) completed at least 1 CHW visit, and 20 of 49 (41%) completed the intervention. 7 individuals who needed assistance with insurance obtained insurance, and 15 of 20 (75%) scheduled an appointment with a primary care physician within 180 days. Participants reported that the US health care previously seemed inaccessible but gained insurance, the ability to navigate the system, and the ability to help others in their community to access medical care because of the program.LimitationsSmall sample size and a single community may limit generalizability.ConclusionsWe reported the acceptability of a CHW intervention. We encountered challenges with feasibility and identified strategies to overcome them. Studies are needed to test the effect of CHW interventions on outcomes and kidney health disparities.FundingNational Kidney Foundation young investigator research grant to Dr Novick.Plain language summaryLatinx individuals are at a higher risk for kidney failure than non-Latinx White individuals; however, they are less likely to receive pre-kidney failure medical care. We piloted a community health worker intervention that connected people with risk factors or showed evidence of kidney dysfunction at community screening events with medical care. Our findings indicate the acceptability of the intervention. We encountered challenges with feasibility and identified strategies to overcome them.

Dataset Information

APOL1 risk alleles among individuals with CKD in Northern Tanzania: A pilot study.

Publications

APOL1 risk alleles among individuals with CKD in Northern Tanzania: A pilot study.

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