Validation of the World Health Organization/ International Society of Hypertension (WHO/ISH) cardiovascular risk predictions in Sri Lankans based on findings from a prospective cohort study.

INTRODUCTION AND OBJECTIVES: There are no cardiovascular (CV) risk prediction models for Sri Lankans. Different risk prediction models not validated for Sri Lankans are being used to predict CV risk of Sri Lankans. We validated the WHO/ISH (SEAR-B) risk prediction charts prospectively in a population-based cohort of Sri Lankans. METHOD: We selected 40-64 year-old participants from the Ragama Medical Officer of Health (MOH) area in 2007 by stratified random sampling and followed them up for 10 years. Ten-year risk predictions of a fatal/non-fatal cardiovascular event (CVE) in 2007 were calculated using WHO/ISH (SEAR-B) charts with and without cholesterol. The CVEs that occurred from 2007-2017 were ascertained. Risk predictions in 2007 were validated against observed CVEs in 2017. RESULTS: Of 2517 participants, the mean age was 53.7 year (SD: 6.7) and 1132 (45%) were males. Using WHO/ISH chart with cholesterol, the percentages of subjects with a 10-year CV risk <10%, 10-19%, 20%-29%, 30-39%, ≥40% were 80.7%, 9.9%, 3.8%, 2.5% and 3.1%, respectively. 142 non-fatal and 73 fatal CVEs were observed during follow-up. Among the cohort, 9.4% were predicted of having a CV risk ≥20% and 8.6% CVEs were observed in the risk category. CVEs were within the predictions of WHO/ISH charts with and without cholesterol in both high (≥20%) and low(<20%) risk males, but only in low(<20%) risk females. The predictions of WHO/ISH charts, with-and without-cholesterol were in agreement in 81% of subjects (ĸ = 0.429; p<0.001). CONCLUSIONS: WHO/ISH (SEAR B) risk prediction charts with-and without-cholesterol may be used in Sri Lanka. Risk charts are more predictive in males than in females and for lower-risk categories. The predictions when stratifying into 2 categories, low risk (<20%) and high risk (≥20%), are more appropriate in clinical practice.

Validity and reliability of the Sri Lankan version of the kidney disease quality of life questionnaire (KDQOL-SF™).

BACKGROUND: The disabling symptoms, various food and fluid restrictions, restrictions to social life and stigma and taboos attached to Chronic Kidney Disease (CKD), have shown to pose a significant bearing on a patient's Quality of Life (QOL). In the present study the Kidney Disease QOL-Short Form (KDQOL-SF™) was culturally adapted, modified and translated into Sinhala and validity and reliability were assessed. METHOD: The process to culturally adapt the Kidney Disease Specific Component (KDSC) of KDQOL-SF™ was carried out by the modified Delphi process with a group of experts. The construct validity of the KDSC was assessed using Exploratory Factor Analysis (EFA). Appraising construct validity of SF-36 component of KDQOL-SF™ was done by assessing the convergent and discriminant validity using the Multitrait-Multimethod Matrix technique (MTMM). Randomly selected 250 CKD patients attending the five renal clinics in Polonnauwa were used to assess the construct validity. To assess the test-retest reliability of the instrument, within a period of one week, 30 randomly selected study participants were visited at their households. RESULTS: Two hundred and fifty adults with documented evidence of CKD participated. The EFA carried out using principal component factoring method and rotated by Varimax orthogonal method resulted in 14 factors with Eigen values ranging from 1.062-8.746. This 14 factor model explained 84.1% of total variance of the initial system. The communalities extracted for domains were all close to one. All the items were loaded to one or more domains with factor coefficients of more than 0.4, not requiring any of the items to be dropped. Few items which showed similarly high factor coefficients in more than one factor were assigned to a factor ensuring the pattern in the theoretical framework of the questionnaire based on expert opinion and vigorous analysis of literature. Convergent and divergent validity assessed using MTMM, revealed satisfactory construct validity. Cronbach's alpha of all domains of KDQOL-SF™ except for cognitive function and Social function, exceeded Nunnally's criteria of 0.7. The Intra class Correlation Coefficients (ICC) were more than 0.8 for all the domains, which indicated good test re-test reliability. CONCLUSIONS: KDQOL-SF™ is a valid and reliable instrument which can be used to assess QOL of CKD patients in Sri Lanka.

A new method to estimate the population size of coconut mite, Aceria guerreronis, on a coconut.

Studies of the coconut mite, Aceria guerreronis, often require accurate assessment of the population density on individual infested coconuts. Here an efficient and accurate method was developed to estimate its population density on an infested coconut. The coconut mites were removed by washing the bracts and surface of an infested coconut with 30 ml of a detergent solution. Shaking the wash for 5 s allowed the mites to distribute uniformly. The number of mites in the first 1 ml of the first wash (X) yielded a very accurate predictor of the total number of mites on a coconut (Y): Y = 30.1X (R2 = 0.99; p <0.0001), also confirming that the wash was indeed homogeneous. The advantages and disadvantages of this method are discussed.

Distribution patterns of coconut mite, Aceria guerreronis, and its predator Neoseiulus aff. paspalivorus in coconut palms.

Distribution patterns and numerical variability of the coconut mite Aceria guerreronis Keifer (Acari: Eriophyidae) and its predator Neoseiulus aff. paspalivorus DeLeon (Phytoseiidae) on the nuts of 3- to 7-month-old bunches of coconut palms were studied at two sites in Sri Lanka. At the two sites, coconut mites were present on 88 and 75% of the nuts but no more than three-quarters of those nuts showed damage symptoms. N. aff. paspalivorus was found more on mature nuts than on immature nuts. Spatial and temporal distribution of coconut mites and predatory mites differed significantly. The mean number of coconut mites per nut increased until 5-month-old bunches and declined thereafter. The densities of predatory mites followed a similar trend but peaked 1 month later. Variability in the numbers of mites among palms and bunches of the same age was great, but was relatively low on 6-month-old bunches. The results indicate that assessment of infestation levels by damage symptoms alone is not reliable. Sampling of coconut and/or predatory mite numbers could be improved by using several nuts of 6-month-old bunches. The effect of predatory mites on coconut mites over time suggests that N. aff. paspalivorus could be a prospective biological control agent of A. guerreronis.