Page 288 - HIVMED_v21_i1.indb

Page 6 of 8 Original Research

Our study demonstrated that PLWH/DM had a higher significantly increased by 10% for every unit increase in DM
frequency of hyponatraemia compared with HIV-uninfected duration. This could be attributed to dysautonomia in long-
patients with DM (18.75% vs. 13.4%). The increased frequency standing DM which impairs the conversion of prorenin to
of hyponatraemia in PLWH/DM could be attributed to the renin and predisposes to hyporeninaemic hypo-aldosteronism
additive effect of HIV on sodium homeostasis. Hyponatraemia and associated hyperkalaemia. 29
is a common electrolyte disorder in PLWH and a possible
marker of HIV severity, as patients with hyponatraemia Calcium
have significantly lower CD4 counts, higher viral loads
and an increased prevalence of acquired immunodeficiency Calcium homeostasis is strongly regulated by parathyroid
16
syndrome (AIDS). In PLWH, the main causes of hormone and vitamin D. Factors contributing to
hyponatraemia include opportunistic infections which hypocalcaemia in HIV and DM include vitamin D deficiency,
predispose to SIADH, adrenal insufficiency, diarrhoea and hypoparathyroidism and hypomagnesaemia. 9,30 Our study
17
vomiting. Furthermore, dysfunction of the thick ascending identified hypocalcaemia as the most common electrolyte
limb of the loop of Henle secondary to HIV and inflammation abnormality in both PLWH/DM and HIV-uninfected patients
results in impaired free water clearance and dilutional with DM. Furthermore, serum calcium was the only
hyponatraemia. 8,18 electrolyte with median levels significantly lower in PLWH/
DM compared with HIV-uninfected patients with DM.
People living with HIV and DM may be at a higher risk of Similarly, Keuhn et al. identified mean serum calcium levels
hyponatraemia because of contributory factors from both to be significantly lower in HIV-infected patients compared
HIV and DM. Furthermore, hyponatraemia in the black with controls (p < 0.0001), irrespective of serum albumin
30
African population may indicate a greater degree of sodium levels. Hypocalcaemia is also common in patients with DM,
imbalance compared with other ethnic groups as the black with a study in Sudan showing significantly lower mean
population physiologically have increased sodium retention serum calcium levels in patients with DM compared with
31
with lower plasma renin and aldosterone levels. 19,20 controls (p < 0.05). Furthermore, vitamin D deficiency in the
elderly is common despite consistent vitamin D intake and
may predispose to hypocalcaemia. Notably, our study
32
Potassium demonstrated a significant inverse association between
Hyperkalaemia is common in DM. 7,21,22 Conversely, studies serum calcium and age in HIV-uninfected patients with DM.
conducted in Nigeria and Saudi Arabia found a predominant A significant association between serum calcium and age
hypokalaemia and no significant association between serum may have not been detected in PLWH/DM as they were
potassium levels and glycaemic control, respectively. 23,24 significantly younger. The degree of sunlight exposure was
Similarly, our study found no significant association between not documented in this study. Although PLWH/DM were
HbA1c and serum potassium levels. Common causes of significantly younger than HIV-uninfected patients with DM,
hyperkalaemia in DM and HIV include hyporeninaemic clinically this difference in age should not usually result in a
hypo-aldosteronism, acidosis, renal impairment and greater proportion of HIV-uninfected patients being
drugs such as angiotensin-converting enzyme (ACE) housebound. Therefore, the significant inverse association
inhibitors, potassium-sparing diuretics and beta-blockers between serum calcium levels and age in HIV-uninfected
8,9
Hypokalaemia in DM is frequently caused by insulin patients may be influenced by factors besides sun exposure.
administration, malabsorption, osmotic diuresis and
hypomagnesaemia. In PLWH, hypokalaemia is commonly The mechanism of vitamin D deficiency in HIV is
9
caused by vomiting, diarrhoea and proximal tubular multifactorial and involves the inhibitory effect of pro-
dysfunction secondary to TDF. 25,26,27 However, in our study, inflammatory cytokines that reduces renal 1-α hydroxylation
TDF was not significantly associated with hypokalaemia. of vitamin D and the consumption of vitamin D by
This could be attributed to our study having relatively macrophages and lymphocytes. Furthermore, vitamin D
33
young PLWH that were on ART for a median duration of 6 has a significant immunomodulatory role, and deficiencies in
years and only 12.5% of PLWH having an eGFR < 60ml/ PLWH are associated with lower CD4 cell counts, higher
min/1.73m , which may reduce the risk of TDF induced viral loads, HIV progression and an increased risk of
2
34
nephrotoxicity. opportunistic infections. Moreover, studies have suggested
that vitamin D deficiency and low calcium levels result in
Notably, our study determined that for every unit increase in impaired insulin synthesis and secretion with subsequent
DM duration, the odds of hypokalaemia significantly glucose intolerance and insulin resistance. The European
15
increased by 97% in PLWH/DM. This could be attributed to AIDS Clinical Society (EACS) has vitamin D supplementation
patients with comorbid HIV and DM developing a greater recommendations and reports that the prevalence of low
degree of insulin resistance, as both conditions progress, vitamin D levels was up to 80% in HIV cohorts and was
28
and therefore require higher doses of insulin to achieve associated with an increased risk of osteoporosis, type 2 DM,
35
glycaemic control with a propensity for hypokalaemia. This mortality and AIDS events. This is in contrast to South
possible contributory factor needs to be explored further as African HIV and DM guidelines, which do not have vitamin
our study did not evaluate the use of insulin. In HIV- D deficiency recommendations despite our susceptible
uninfected patients with DM, the likelihood of hyperkalaemia population. 36,37

http://www.sajhivmed.org.za 280 Open Access