Diagnostic testing for hypertension, diabetes, and hypercholesterolaemia in low-income and middle-income countries: a cross-sectional study of data for 994 185 individuals from 57 nationally representative surveys

BACKGROUND

Testing for the risk factors of cardiovascular disease, which include hypertension, diabetes, and hypercholesterolaemia, is important for timely and effective risk management. Yet few studies have quantified and analysed testing of cardiovascular risk factors in low-income and middle-income countries (LMICs) with respect to sociodemographic inequalities. We aimed to address this knowledge gap.

METHODS

In this cross-sectional analysis, we pooled individual-level data for non-pregnant adults aged 18 years or older from nationally representative surveys done between Jan 1, 2010, and Dec 31, 2019 in LMICs that included a question about whether respondents had ever had their blood pressure, glucose, or cholesterol measured. We analysed diagnostic testing performance by quantifying the overall proportion of people who had ever been tested for these cardiovascular risk factors and the proportion of individuals who met the diagnostic testing criteria in the WHO package of essential noncommunicable disease interventions for primary care (PEN) guidelines (ie, a BMI >30 kg/m2 or a BMI >25 kg/m2 among people aged 40 years or older). We disaggregated and compared diagnostic testing performance by sex, wealth quintile, and education using two-sided t tests and multivariable logistic regression models.

FINDINGS

Our sample included data for 994 185 people from 57 surveys. 19·1% (95% CI 18·5-19·8) of the 943 259 people in the hypertension sample met the WHO PEN criteria for diagnostic testing, of whom 78·6% (77·8-79·2) were tested. 23·8% (23·4-24·3) of the 225 707 people in the diabetes sample met the WHO PEN criteria for diagnostic testing, of whom 44·9% (43·7-46·2) were tested. Finally, 27·4% (26·3-28·6) of the 250 573 people in the hypercholesterolaemia sample met the WHO PEN criteria for diagnostic testing, of whom 39·7% (37·1-2·4) were tested. Women were more likely than men to be tested for hypertension and diabetes, and people in higher wealth quintiles compared with those in the lowest wealth quintile were more likely to be tested for all three risk factors, as were people with at least secondary education compared with those with less than primary education.

INTERPRETATION

Our study shows opportunities for health systems in LMICs to improve the targeting of diagnostic testing for cardiovascular risk factors and adherence to diagnostic testing guidelines. Risk-factor-based testing recommendations rather than sociodemographic characteristics should determine which individuals are tested.

FUNDING

Harvard McLennan Family Fund, the Alexander von Humboldt Foundation, and the National Heart, Lung, and Blood Institute of the US National Institutes of Health.

Genetic analysis of heat shock proteins in maize

A genetic analysis of heat shock protein (HSP) synthesis was performed in seedling leaf tissue of two maize inbred lines, their F1 hybrid and F2 progeny. Protein synthesis following a high temperature treatment was visualized by [(35)S]-methionine in vivo labelling and two-dimensional gel electrophoresis. The parental lines' HSP synthesis patterns revealed both qualitative and quantitative polymorphisms implicative of differences in HSP structural genes and regulatory factors. The F1 hybrid HSP profile indicated that synthesis of all parental HSPs conformed to dominant inheritance patterns, including complete dominance, over-dominance and co-dominance. Alleles for six low-molecularweight HSPs in F2 progeny assorted according to typical 3∶1 Mendelian ratios for dominant gene expression. There is evidence for unlinked gene loci of four different HSP gene pairs, but data for three other HSP gene pairs were inconclusive, perhaps reflecting linkage for one pair and complex regulatory factor interactions for the other two pairs of genes. These results clearly indicate the existence of genetic variability in HSP synthesis and emphasize the potential of partitioning their roles in thermal tolerance using genetic and molecular analyses.

Genotype-specific heat shock proteins in two maize inbreds

Leaf blade tissue of maize inbred lines B73 and Mo17 was analyzed for intraspecific genetic variability in the heat shock response. The maize inbreds were characterized for acquired thermal tolerance and patterns of heat shock protein synthesis. The leakage conductivity assay of membrane stability during stress indicated that Mol7 possesses greater potential than B73 to acquire thermal tolerance. Poly(A)(+) RNA, extracted from leaf blades, was translated in vitro in the presence of (35)S-methionine and the translation products separated by twodimensional gel electrophoresis. Major genotypic differences were observed in the translation products. Mo 17 synthesized twelve unique heat shock proteins in the 15-18 kD range, but B73 synthesized only three unique heat shock proteins in the same range. DNA polymorphisms were observed between the maize lines using (32)P labeled heat shock protein gene probes.

A study of donor alloreactivity, which may predict acute graft-versus-host disease in HLA identical bone marrow transplantations for early leukaemia

Recent studies performed in Seattle, USA have suggested that pretransplant assignment of high or low donor alloreactivity may predict acute graft-versus-host disease (aGvHD) after allogeneic HLA identical marrow transplantation for acute leukaemia. The effect of such pretransplant assignment was studied in a Scandinavian population of 114 consecutive transplantations for acute and chronic leukaemias in 1st remission (n = 74) or chronic phase (n = 40) performed between 1975 and 1989. The selected cut-off value for discriminating between donors of high and low responding capacity (DRC) was based on distribution plots of results from the pretransplant mixed lymphocyte culture (MLC) and chosen as the median value (80% normalized response). Then 57 donors were assigned with high DRC and 57 donors assigned with low DRC. Kaplan-Meier estimates of the probability of patients to develop Grade II or higher aGvHD in receipt of high or low responder donor transplants were compared by univariant analysis. The patients in first remission or chronic phase transplanted with bone marrow from donors assigned as high or low responders had a 36.1% and 10.6% risk for aGvHD, respectively, a difference found to be significant by log rank test (chi-squared = 10.1, d.f. = 1, P = 0.0015). Subsequent studies of the cellular and humoral requirements for this predictive response of donor cells, by blocking with cytokine specific antibodies, addition of excess of recombinant human cytokines and scanning of lymphocyte subsets during the response, showed that the response against pool cells mostly depended upon IL-2 responding cells with the phenotype CD3+, CD4+, CD8-, CD25+, CD16-. It is concluded that prospective studies of alloreactivity as a risk factor should be performed to confirm the above findings.