Page 284 - HIVMED_v21_i1.indb

Page 2 of 8 Original Research

Electrolytes play a vital role in maintaining homeostasis and DM included in the study could have either type 1 or type 2
are paramount in mediating enzymatic reactions, cellular DM, be on ART or antiretroviral-naïve, have any degree of
function and electrical gradients. Patients with HIV or DM renal function that was determined by the estimated
7
are predisposed to electrolyte abnormalities because of glomerular filtration rate (eGFR) and be on medication for
8,9
multifactorial pathophysiological factors. The risk of comorbidities. Patients with incomplete records were
nephropathy, with subsequent electrolyte abnormalities, excluded from the study. Sample sizes were determined by
increases in the setting of comorbid HIV and DM. applying a power analysis in G*Power, which used an alpha
Furthermore, the black African population has distinct of 0.05, a power of 0.80 and a medium effect size of 0.4. The
electrolyte physiology and a predisposition to chronic kidney ratio of cases and controls was 1:2, and participants were
10
disease and HIV-associated nephropathy (HIVAN). In selected by random sampling, matched by eGFR. Estimated
addition, the use of tenofovir (TDF) increases the risk of glomerular filtration rate was stratified by the Kidney Disease
proximal tubular dysfunction and subsequent hypokalaemia Outcomes Quality Initiative (KDOQI) classification. Data
and hypophosphataemia. 11 were anonymised with reference numbers. Variables
analysed included the following:
The Atherosclerosis Risk in Communities (ARIC) study • age (years)
concluded that African American patients had an • sex
approximately twofold greater incidence of type 2 DM • HIV status
12
compared with white patients. Although this racial disparity • type of DM
is multifactorial, lower vitamin D and serum potassium • duration of DM (years)
13
levels in the black population are being explored as possible • duration of HIV (years)
14
contributory factors. Importantly, the prevalence of vitamin • duration of ART (years)
D deficiency in type 2 DM is disproportionately elevated in • type of ART
African American people compared with other ethnic groups • eGFR (mL/min/1.73m )
2
in the USA. 15 • levels of serum sodium, potassium, corrected calcium
and phosphate (mmol/L)
Electrolyte abnormalities are associated with increased • levels of glycated haemoglobin (HbA1c) (%).
morbidity and mortality, even if they are chronic or of mild
severity and may remain clinically silent until an advanced The following serum electrolyte reference ranges, as per the
stage. However, there is a paucity of data from Africa National Health Laboratory Services (NHLS), were utilised:
8,9
regarding electrolyte abnormalities in HIV or DM. • sodium: 136 mmol/L – 145 mmol/L
Furthermore, there are no studies assessing electrolyte • potassium: 3.5 mmol/L – 5.1 mmol/L
abnormalities in black African people living with HIV • calcium: 2.20 mmol/L – 2.55 mmol/L
and diabetes mellitus (PLWH/DM). Determining and • phosphate: 0.78 mmol/L – 1.42 mmol/L
understanding the spectrum of electrolyte abnormalities in
black African PLWH/DM are of crucial significance, Any electrolyte values below the lower limit of normal were
particularly in South Africa, which has a large burden of HIV considered hypo-electrolyte abnormalities, whilst those
and DM and is undergoing an epidemiological transition in a above the upper limit of normal were considered hyper-
resource-limited setting. electrolyte abnormalities. Corrected serum calcium levels
were utilised and calculated as follows: measured total
The objective of this retrospective case–control study was calcium (mmol/L) + 0.02 (40 [g/L] – serum albumin [g/L]).
to determine, compare and identify associated factors The 2017 Society for Endocrinology, Metabolism and
regarding serum electrolyte abnormalities (sodium, Diabetes of South Africa (SEMDSA) guidelines advocate for
potassium, calcium and phosphate) in black African PLWH/ an HbA1c ≤ 7% to prevent micro- and macro-vascular
DM versus black African HIV-uninfected patients with DM complications. Therefore, in this study, adequate glycaemic
who attended the Edendale Hospital DM clinic from control was defined as HbA1c ≤ 7%. Estimated glomerular
01 January to 31 December 2016. filtration rate was calculated by using the Modification of
Diet in Renal Disease (MDRD) formula. Serum electrolytes,
Methods eGFR and HbA1c were measured by using the Siemens
Dimension analyser.
®
This quantitative retrospective case–control study was
conducted in 96 black African PLWH/DM (cases) and 192
black African HIV-uninfected patients with DM (controls) Statistical analysis
attending the Edendale Hospital DM clinic, Pietermaritzburg, Data were captured by using Microsoft Excel, version 2016
KwaZulu-Natal, South Africa, over 1 year from 01 January to (Microsoft, USA). Statistical analyses were conducted by
31 December 2016. Records of patients attending the DM using Statistical Analysis Software (SAS), version 9.4 (SAS
clinic were analysed retrospectively from datasheets. Institute Inc., Cary, NC, USA). Continuous variables were
Electrolytes were measured during routine outpatient visits expressed as medians with interquartile ranges (IQRs).
at the Edendale Hospital DM clinic. Black African PLWH/ Categorical variables were expressed as frequencies and

http://www.sajhivmed.org.za 276 Open Access