Comparison of Two Different Semiquantitative Urinary Dipstick Tests with Albumin-to-Creatinine Ratio for Screening and Classification of Albuminuria According to KDIGO. A Diagnostic Test Study.

BACKGROUND: Semiquantitative dipstick tests are utilized for albuminuria screening. METHODS: In a prospective cross-sectional survey, we analyzed the diagnostic test validity of the semiquantitative colorimetric indicator-dye-based Combur9-Test® and the albumin-specific immunochromatographic assay Micral-Test® for the detection of albuminuria, the distribution of the semiquantitative measurements within the albuminuria stages according to KDIGO, and the utility for albuminuria screening compared with an albumin-to-creatinine ratio (ACR) in a walk-in population. RESULTS: In 970 subjects, albuminuria (≥30 mg/g) was detected in 12.7% (95% CI 85.6-96.3%) with the ACR. Sensitivity was 82.9% (95% CI 75.1-89.1%) and 91.9% (95% CI 88.7-96.9%) and specificity 71.5% (95% CI 68.4-74.6%) and 17.5% (95% CI 15.0-20.2%) for the Combur9-Test® and Micral-Test®, respectively. Correct classification to KDIGO albuminuria stages A2/A3 with the Combur9-Test® was 15.4%, 51.4%, and 87.9% at cut-offs of 30, 100, and ≥300 mg/dL, and with the Micral-Test® it was 1.8%, 10.5%, and 53.6% at cut-offs of 2, 5, and 10 mg/dL, respectively. Overall, disagreement to KDIGO albuminuria was seen in 27% and 73% with the Combur9-Test® and Micral-Test®, respectively. From the total population, 62.5% and 15.3% were correctly ruled out and 2.2% and 1% were missed as false-negatives by the Combur9-Test® and Micral-Test®, respectively. CONCLUSION: Compared to the Combur9-Test®, the utility of the Micral-Test® is limited, because the fraction of correctly ruled out patients is small and a large proportion with a positive Micral-Test® require a subsequent ACR conformation test.

Assessment of diabetes and prediabetes prevalence and predictors by HbA1c in a population from sub-Saharan Africa with a high proportion of anemia: a prospective cross-sectional study.

INTRODUCTION: Epidemiological data about diabetes mellitus (DM) for sub-Saharan Africa (SSA) are scarce and the utility of glycated hemoglobin (HbA1c) to diagnose DM is uncertain in African populations with a high proportion of anemia. RESEARCH DESIGN AND METHODS: In a cross-sectional study, age-adjusted prevalence rates and predictors for DM and pre-DM were prospectively assessed by HbA1c in a semirural walk-in population of Tanzania (n=992). Predictors for DM were calculated by logistic regression. Correlations between HbA1c, hemoglobin, and blood glucose levels were done by Pearson's correlation. RESULTS: Overall, DM and pre-DM prevalence rates were 6.8% (95% CI 5.3 to 8.5) and 25% (95% CI 22.8 to 28.3), respectively. There was an increase in DM prevalence in patients 50-59 (14.9%; 95% CI 9.1 to 22.5), ≥60 years old (18.5%; 95% CI 12.2 to 26.2) and in patients with overweight (9.3%; 95% CI 5.9 to 13.7), obesity (10.9%; 95% CI 6.9 to 16) compared with patients 18-29 years old (2.2%; 95% CI 0.9 to 4.4) (p<0.001) and to normal-weight patients (3.6%; 95% CI 2.1 to 5.6) (p<0.01), respectively. Age (OR 1.08, 95% CI 1.05 to 1.12; p<0.001), body mass index (BMI) (OR 1.10, 95% CI 1.04 to 1.16; p<0.001), and acute infection (OR 3.46, 95% CI 1.02 to 10.8; p=0.038) were predictors for DM. Comparing patients with a BMI of 20 kg/m2 and a BMI of 35 kg/m2, the relative risk for DM increases in average by 2.12-fold (range 1.91-2.24) across the age groups. Comparing patients 20 years old with patients 70 years old, the relative risk for DM increases in average 9.7-fold (range 8.9-10.4) across the BMI groups. Overall, 333 patients (36%) suffered from anemia. Pearson's correlation coefficients (r) between HbA1c and hemoglobin was -0.009 (p=0.779), and between HbA1c and fasting blood glucose and random blood glucose, it was 0.775 and 0.622, respectively (p<0.001). CONCLUSION: We observed a high prevalence of DM and pre-DM, mainly triggered by increasing age and BMI, and provide evidence that HbA1c is suitable to assess DM also in populations of SSA with high proportions of anemia. TRIAL REGISTRATION NUMBER: NCT03458338.

The epidemiology of chronic kidney disease and the association with non-communicable and communicable disorders in a population of sub-Saharan Africa.

In sub-Saharan Africa (SSA), epidemiological data for chronic kidney disease (CKD) are scarce. We conducted a prospective cross-sectional study including 952 patients in an outpatient clinic in Tanzania to explore CKD prevalence estimates and the association with cardiovascular and infectious disorders. According to KDIGO, we measured albumin-to-creatinine ratio and calculated eGFR using CKD-EPI formula. Factors associated with CKD were calculated by logistic regression. Venn diagrams were modelled to visualize interaction between associated factors and CKD. Overall, the estimated CKD prevalence was 13.6% (95% CI 11-16%). Ninety-eight patients (11.2%) (95% CI 9-14%) were categorized as moderate, 12 (1.4%) (95% CI 0-4%) as high, and 9 (1%) (95% CI 0-3%) as very high risk according to KDIGO. History of tuberculosis (OR 3.75, 95% CI 1.66-8.18; p = 0.001) and schistosomiasis (OR 2.49, 95% CI 1.13-5.18; p = 0.02) were associated with CKD. A trend was seen for increasing systolic blood pressure (OR 1.02 per 1 mmHg, 95% CI 1.00-1.03; p = 0.01). Increasing BMI (OR 0.92 per 1kg/m2, 95% CI 0.88-0.96; p = <0.001) and haemoglobin (OR 0.82 per 1g/dL, 95% CI 0.72-0.94; p = 0.004) were associated with risk reduction. Diabetes was associated with albuminuria (OR 2.81, 95% CI 1.26-6.00; p = 0.009). In 85% of all CKD cases at least one of the four most common factors (hypertension, diabetes, anaemia, and history of tuberculosis or schistosomiasis) was associated with CKD. A singular associated factor was found in 61%, two in 14%, and ≥3 in 10% of all CKD cases. We observed a high prevalence estimate for CKD and found that both classical cardiovascular and neglected infectious diseases might be associated with CKD in a semi-rural population of SSA. Our finding provides further evidence for the hypothesis that the "double burden" of non-communicable and endemic infectious diseases might affect kidney health in SSA.

Cloning and disruption of the Pichia pastoris ARG1, ARG2, ARG3, HIS1, HIS2, HIS5, HIS6 genes and their use as auxotrophic markers.

Screening of a partial genomic database of Pichia pastoris allowed us to identify the ARG1, ARG2, ARG3, HIS1, HIS2, HIS5 and HIS6 genes, based on homology to their Saccharomyces cerevisiae counterparts. Based on the cloned sequences, a set of disruption vectors was constructed, using the previously described PpURA5-blaster as a selectable marker, and the cloned genes were individually disrupted. All disruptants exhibited the expected auxotrophic phenotypes, with only the his2 knockouts displaying a bradytroph phenotype. To allow their use as auxotrophic markers, we amplified the open reading frames and respective promoters and terminator regions of PpARG1, PpARG2, PpARG3, PpHIS1, PpHIS2 and PpHIS5. We then designed a set of integration vectors harbouring cassettes of the ARG pathway as selectable markers, to disrupt the genes of the HIS pathway and vice versa. Employing this strategy, we devised a scheme allowing for the rapid and stable introduction of several heterologous genes into the genome of P. pastoris without the need for recyclable markers or strains with multiple auxotrophies. Furthermore, simple replica-plating, instead of cost-consuming and labour-intensive colony PCR or Southern analysis, can be used to identify positive transformants, making this approach amendable for initial high-throughput applications, which can then be followed up by a more careful analysis of the selected transformants.