AIMS: We explored if the association is explained by shared risk factors or is independent and whether there are regional or stroke subtype variations.
METHODS: INTERSTROKE is a case-control study and the largest international study of risk factors for first acute stroke, completed in 27 countries. We included individuals with available serum creatinine values and calculated estimated glomerular filtration rate (eGFR). Renal impairment was defined as eGFR <60 mL/min/1.73 m2. Multivariable conditional logistic regression was used to determine the association of renal function with stroke.
RESULTS: Of 21,127 participants, 41.0% were female, the mean age was 62.3 ± 13.4 years, and the mean eGFR was 79.9 ± 23.5 mL/min/1.73 m2. The prevalence of renal impairment was higher in cases (22.9% vs. 17.7%, p < 0.001) and differed by region (p < 0.001). After adjustment, lower eGFR was associated with increased odds of stroke. Renal impairment was associated with increased odds of all stroke (OR 1.35; 95% CI: 1.24-1.47), with higher odds for intracerebral hemorrhage (OR 1.60; 95% CI: 1.35-1.89) than ischemic stroke (OR 1.29; 95% CI: 1.17-1.42) (pinteraction 0.12). The largest magnitudes of association were seen in younger participants and those living in Africa, South Asia, or South America (pinteraction < 0.001 for all stroke). Renal impairment was also associated with poorer clinical outcome (RRR 2.97; 95% CI: 2.50-3.54 for death within 1 month).
CONCLUSION: Renal impairment is an important risk factor for stroke, particularly in younger patients, and is associated with more severe stroke and worse outcomes.
METHODS: We analysed the availability, costs, and affordability of blood pressure-lowering medicines with data recorded from 626 communities in 20 countries participating in the Prospective Urban Rural Epidemiological (PURE) study. Medicines were considered available if they were present in the local pharmacy when surveyed, and affordable if their combined cost was less than 20% of the households' capacity to pay. We related information about availability and affordability to use of these medicines and blood pressure control with multilevel mixed-effects logistic regression models, and compared results for high-income, upper-middle-income, lower-middle-income, and low-income countries. Data for India are presented separately because it has a large generic pharmaceutical industry and a higher availability of medicines than other countries at the same economic level.
FINDINGS: The availability of two or more classes of blood pressure-lowering drugs was lower in low-income and middle-income countries (except for India) than in high-income countries. The proportion of communities with four drug classes available was 94% in high-income countries (108 of 115 communities), 76% in India (68 of 90), 71% in upper-middle-income countries (90 of 126), 47% in lower-middle-income countries (107 of 227), and 13% in low-income countries (nine of 68). The proportion of households unable to afford two blood pressure-lowering medicines was 31% in low-income countries (1069 of 3479 households), 9% in middle-income countries (5602 of 65 471), and less than 1% in high-income countries (44 of 10 880). Participants with known hypertension in communities that had all four drug classes available were more likely to use at least one blood pressure-lowering medicine (adjusted odds ratio [OR] 2·23, 95% CI 1·59-3·12); p<0·0001), combination therapy (1·53, 1·13-2·07; p=0·054), and have their blood pressure controlled (2·06, 1·69-2·50; p<0·0001) than were those in communities where blood pressure-lowering medicines were not available. Participants with known hypertension from households able to afford four blood pressure-lowering drug classes were more likely to use at least one blood pressure-lowering medicine (adjusted OR 1·42, 95% CI 1·25-1·62; p<0·0001), combination therapy (1·26, 1·08-1·47; p=0·0038), and have their blood pressure controlled (1·13, 1·00-1·28; p=0·0562) than were those unable to afford the medicines.
INTERPRETATION: A large proportion of communities in low-income and middle-income countries do not have access to more than one blood pressure-lowering medicine and, when available, they are often not affordable. These factors are associated with poor blood pressure control. Ensuring access to affordable blood pressure-lowering medicines is essential for control of hypertension in low-income and middle-income countries.
FUNDING: Population Health Research Institute, the Canadian Institutes of Health Research, Heart and Stroke Foundation of Ontario, Canadian Institutes of Health Research Strategy for Patient Oriented Research through the Ontario SPOR Support Unit, the Ontario Ministry of Health and Long-Term Care, pharmaceutical companies (with major contributions from AstraZeneca [Canada], Sanofi Aventis [France and Canada], Boehringer Ingelheim [Germany amd Canada], Servier, and GlaxoSmithKline), Novartis and King Pharma, and national or local organisations in participating countries.
METHODS: From June 2015 to Jan 2018, a total of 4,603 adults were enrolled from 628 communities in 18 countries and 7 regions of the world. Each participant performed concurrent measurements from the MicroGP and EasyOne spirometer. Measurements were compared by the intra-class correlation coefficient (ICC) and Bland-Altman method.
RESULTS: Approximately 65% of the participants achieved clinically acceptable quality measurements. Overall correlations between paired FEV1 (ICC 0.88 [95% CI 0.87, 0.88]) and FVC (ICC 0.84 [0.83, 0.85]) were high. Mean differences between paired FEV1 (-0.038 L [-0.053, -0.023]) and FVC (0.033 L [0.012, 0.054]) were small. The 95% limits of agreement were wide but unbiased (FEV1 984, -1060; FVC 1460, -1394). Similar findings were observed across regions. The source of variation between spirometers was mainly at the participant level. Older age, higher body mass index, tobacco smoking and known COPD/asthma did not adversely impact on the inter-device variability. Furthermore, there were small and acceptable mean differences between paired FEV1 and FVC z-scores using the Global Lung Initiative normative values, suggesting minimal impact on lung function interpretation.
CONCLUSIONS: In this multicenter, diverse community-based cohort study, measurements from two portable spirometers provided good correlation, small and unbiased differences between measurements. These data support their interchangeable use across diverse populations to provide accurate trends in serial lung function measurements in epidemiological studies.