Purpose Vitamin D deficiency/insufficiency may increase the susceptibility to COVID-19. We aimed to determine the association between vitamin D deficiency/insufficiency and susceptibility to COVID-19, its severity, mortality and role of vitamin D in its treatment. Methods We searched CINHAL, Cochrane library, EMBASE, PubMED, Scopus, and Web of Science up to 30.05.2021 for observational studies on association between vitamin D deficiency/insufficiency and susceptibility to COVID-19, severe disease and death among adults, and, randomized controlled trials (RCTs) comparing vitamin D treatment against standard care or placebo, in improving severity or mortality among adults with COVID-19. Risk of bias was assessed using Newcastle-Ottawa scale for observational studies and AUB-KQ1 Cochrane tool for RCTs. Study-level data were analyzed using RevMan 5.3 and R (v4∙1∙0). Heterogeneity was determined by I  2 and sources were explored through pre-specified sensitivity analyses, subgroup analyses and meta-regressions. Results Of 1877 search results, 76 studies satisfying eligibility criteria were included. Seventy-two observational studies were included in the meta-analysis (n=1976099). Vitamin D deficiency/insufficiency increased the odds of developing COVID-19 (OR 1∙46, 95% CI 1∙28–1∙65, p<0∙0001, I  2=92%), severe disease (OR 1∙90, 95% CI 1∙52–2∙38, p<0.0001, I  2=81%) and death (OR 2∙07, 95% CI 1∙28–3∙35, p=0.003, I  2=73%). 25-hydroxy vitamin D (25(OH)D) concentration were lower in individuals with COVID-19 compared to controls (mean difference [MD] -3∙85 ng/mL, 95% CI -5∙44,-2∙26, p=<0.0001), in patients with severe COVID-19 compared to controls with non-severe COVID19 (MD -4∙84 ng/mL, 95% CI -7∙32,-2∙35, p=0∙0001) and in non-survivors compared to survivors (MD -4∙80 ng/mL, 95%-CI -7∙89,-1∙71, p=0∙002). The association between vitamin D deficiency/insufficiency and death was insignificant when studies with high risk of bias or studies reporting unadjusted effect estimates were excluded. Risk of bias and heterogeneity were high across all analyses. Discrepancies in timing of vitamin D testing, definitions of severe COVID-19 and vitamin D deficiency/insufficiency partly explained the heterogeneity. Four RCTs were widely heterogeneous precluding meta-analysis. Conclusion Multiple observational studies involving nearly two million adults suggest vitamin D deficiency/insufficiency increases susceptibility to COVID-19 and severe COVID-19, although with a high risk of bias and heterogeneity. Association with mortality was less robust. Heterogeneity in RCTs precluded their meta-analysis.

No abstract

Capillary blood tests measure whole blood glucose as opposed to venous samples which measure plasma glucose. It is used for the care of people with diabetes, as a monitoring tool, giving a guide to blood glucose levels, at a specific moment in time. Capillary blood glucose monitoring was first established in the 1970s using glucometers. With time, the use of glucometers has become easier and faster, with much smaller blood samples, yielding results in a matter of seconds. Today they are used routinely in health care, for the easier achievement of glycaemic targets and diabetic emergencies. Without such technology, intensive glucose control including insulin pump therapy would not have become a reality. Glucometers have also relieved a great amount of anxiety over the management of hypoglycaemia. Today however, we rely so much on capillary blood glucose measurements forgetting its limitations. This article will discuss the pitfalls and limitations of capillary blood glucose monitoring (1, 2). Accuracy goals for home glucose monitorsThe goals for glucometer accuracy have been quite variable. Clarke et al. proposed an accuracy grid to establish a more expansive set of goals for glucometer usage taking into account clinical accuracy, defined as within 20% of the laboratory glucose (3). For glucose levels above 75 mg/dl, the International Organization for Standardization (ISO) recommends a goal for glucometer error of within 20% when compared with a reference glucose sample, but for glucose levels less than 75 mg/dl, the goal is for 95% of readings to be within 15 mg/dl of the reference. The U.S. Food and Drug Administration goal for glucometers is within 20% of the reference value, when glucose is greater than 100 mg/dl and within 20 mg/dl when glucose is less than 100 mg/dl (4, 5).Although there is no universally binding standard, guidelines issued by ISO are widely acknowledged. Assuming a meter meets the ISO guideline, then a true glucose level of 55 mg/dl could in fact yield a reading of as low as 40 or as high as 70 mg/dl. It could be particularly hazardous in a patient with hypoglycaemia unawareness who would consider the reading of 70 mg/dl as reassuring for a true value of 55 mg/dl, which needs prompt corrective action. At the other end of the spectrum, a true value of 350 mg/dl might register as low as 280 or as high as 420 mg/dl. This could have some consequences, especially in intensive care situations, where insulin infusion algorithms aim at achieving tight glycaemic control (4).

Multiple endocrine neoplasia (MEN) type 1 syndrome is an autosomal dominant disorder caused by germline mutations in MEN1 gene, characterized by tumours in endocrine and nonendocrine organs. Giant prolactinoma is defined as tumours larger than 40mm with very high prolactin secretion. We report two unrelated Sri Lankan patients (8-year-old boy and a 20-year-old female) who presented with giant prolactinomas with mass effects of the tumours. The female patient showed complete response to medical therapy, while the boy developed recurrent resistant prolactinoma needing surgery and radiotherapy. During follow-up, both developed pancreatic neuroendocrine tumours. Genetic analysis revealed that one was heterozygous for a nonsense mutation and other for missense mutation in MEN1 gene. Screening confirmed familial MEN-1 syndrome in their families. High clinical suspicion upon unusual clinical presentation prompted genetic evaluation in these patients and detection of MEN1 gene mutation. Pituitary adenomas in children with MEN-1 syndrome are larger tumours with higher rates of treatment resistance. This report emphasizes importance of screening young patients with giant prolactinoma for MEN-1 syndrome and arranging long-term follow-up for them expecting variable treatment outcomes. Sri Lanka requires further studies to describe the genotypic-phenotypic variability of MEN-1 syndrome in this population.

The hemoglobin A1C (HbA1C) assay has become the gold-standard measurement of chronic glycaemia for over two decades. It provides an average blood glucose level during the preceding 10-12 weeks. Its close association with risk for long-term complications, established in epidemiologic studies and clinical trials, has resulted in clinicians using HbA1C test results to guide their treatment decisions, and thus the assay has become the cornerstone of clinical practice. This brief review describes some important facts about HbA1C and its relevance and usefulness in clinical practice.