Additional file 1: Appendix. of Traditional medicine practices among community members with chronic kidney disease in northern Tanzania: an ethnomedical survey

Structured Survey Instrument for the use of Traditional Medicines (English and Swahili) (DOCX 461 kb

Frequency of <i>APOL1</i> G1 and <i>APOL1</i> G2 risk variants for CKD-AFRiKA study sample and other populations of interest.

<p>Frequency of <i>APOL1</i> G1 and <i>APOL1</i> G2 risk variants for CKD-AFRiKA study sample and other populations of interest.</p

Reported frequencies of <i>APOL1</i> G1 and G2 risk alleles for several Bantu populations across sub-Saharan Africa.

<p>Reported frequencies of <i>APOL1</i> G1 and G2 risk alleles for several Bantu populations across sub-Saharan Africa.</p

Characteristics of participants with CKD, by genotyping status; n = 57.

<p>Characteristics of participants with CKD, by genotyping status; n = 57.</p

<i>APOL1</i> risk alleles among individuals with CKD in Northern Tanzania: A pilot study

<div><p>Introduction</p><p>In sub-Saharan Africa, approximately 100 million people have CKD, yet genetic risk factors are not well-understood. Despite the potential importance of understanding <i>APOL1</i> 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 <i>APOL1</i> risk allele frequencies among individuals with CKD.</p><p>Methods</p><p>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 <i>APOL1</i> G1 risk allele and an insertion/deletion polymorphism defining the G2 risk allele. Genotyping was performed in duplicate.</p><p>Results</p><p>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 <i>APOL1</i> G1 SNPs and the <i>APOL1</i> G2 polymorphism. Genotyping quality was high, with all duplicated samples showing perfect concordance. The frequency of <i>APOL1</i> 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).</p><p>Discussion</p><p>In individuals with CKD from northern Tanzania, we demonstrated feasibility of genotyping <i>APOL1</i> 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.</p></div

Development and Validation of a Cross-Cultural Knowledge, Attitudes, and Practices Survey Instrument for Chronic Kidney Disease in a Swahili-Speaking Population

<div><p>Introduction</p><p>Non-communicable diseases are a growing global burden, and structured surveys can identify critical gaps to address this epidemic. In sub-Saharan Africa, there are very few well-tested survey instruments measuring population attributes related to non-communicable diseases. To meet this need, we have developed and validated the first instrument evaluating knowledge, attitudes and practices pertaining to chronic kidney disease in a Swahili-speaking population.</p><p>Methods and Results</p><p>Between December 2013 and June 2014, we conducted a four-stage, mixed-methods study among adults from the general population of northern Tanzania. In stage 1, the survey instrument was constructed in English by a group of cross-cultural experts from multiple disciplines and through content analysis of focus group discussions to ensure local significance. Following translation, in stage 2, we piloted the survey through cognitive and structured interviews, and in stage 3, in order to obtain initial evidence of reliability and construct validity, we recruited and then administered the instrument to a random sample of 606 adults. In stage 4, we conducted analyses to establish test-retest reliability and known-groups validity which was informed by thematic analysis of the qualitative data in stages 1 and 2. The final version consisted of 25 items divided into three conceptual domains: knowledge, attitudes and practices. Each item demonstrated excellent test-retest reliability with established content and construct validity.</p><p>Conclusions</p><p>We have developed a reliable and valid cross-cultural survey instrument designed to measure knowledge, attitudes and practices of chronic kidney disease in a Swahili-speaking population of Northern Tanzania. This instrument may be valuable for addressing gaps in non-communicable diseases care by understanding preferences regarding healthcare, formulating educational initiatives, and directing development of chronic disease management programs that incorporate chronic kidney disease across sub-Saharan Africa.</p></div

Flow diagram.

<p>Participants who were enrolled in the study; CKD-AFRiKA.</p

Demographic, social characteristics, self-reported medical history, and co-morbidities of the study population stratified by CKD risk status; N = 606 (CKD-AFRIKA, 2014).

<p>Demographic, social characteristics, self-reported medical history, and co-morbidities of the study population stratified by CKD risk status; N = 606 (CKD-AFRIKA, 2014).</p

Mean score for knowledge domain by known-groups.

<p>*Reference group for p-value</p><p>Mean score for knowledge domain by known-groups.</p

The Epidemiology of Chronic Kidney Disease in Northern Tanzania: A Population-Based Survey

<div><p>Background</p><p>In sub-Saharan Africa, kidney failure has a high morbidity and mortality. Despite this, population-based estimates of prevalence, potential etiologies, and awareness are not available.</p><p>Methods</p><p>Between January and June 2014, we conducted a household survey of randomly-selected adults in Northern Tanzania. To estimate prevalence we screened for CKD, which was defined as an estimated glomerular filtration rate ≤ 60 ml/min/1.73m2 and/or persistent albuminuria. We also screened for human immunodeficiency virus (HIV), diabetes, hypertension, obesity, and lifestyle practices including alcohol, tobacco, and traditional medicine use. Awareness was defined as a self-reported disease history and subsequently testing positive. We used population-based age- and gender-weights in estimating prevalence, and we used generalized linear models to explore potential risk factors associated with CKD, including living in an urban environment.</p><p>Results</p><p>We enrolled 481 adults from 346 households with a median age of 45 years. The community-based prevalence of CKD was 7.0% (95% CI 3.8-12.3), and awareness was low at 10.5% (4.7-22.0). The urban prevalence of CKD was 15.2% (9.6-23.3) while the rural prevalence was 2.0% (0.5-6.9). Half of the cases of CKD (49.1%) were not associated with any of the measured risk factors of hypertension, diabetes, or HIV. Living in an urban environment had the strongest crude (5.40; 95% CI 2.05-14.2) and adjusted prevalence risk ratio (4.80; 1.70-13.6) for CKD, and the majority (79%) of this increased risk was not explained by demographics, traditional medicine use, socioeconomic status, or co-morbid non-communicable diseases (NCDs).</p><p>Conclusions</p><p>We observed a high burden of CKD in Northern Tanzania that was associated with low awareness. Although demographic, lifestyle practices including traditional medicine use, socioeconomic factors, and NCDs accounted for some of the excess CKD risk observed with urban residence, much of the increased urban prevalence remained unexplained and will further study as demographic shifts reshape sub-Saharan Africa.</p></div