A Comparative Study of Serum Electrolytes, Total Protein, Calcium and Phosphate Among Diabetic and HIV/AIDS Patients in Abakaliki, Southeastern, Nigeria
E Ugwuja, N Eze
and diabetes, electrolytes, haart, hivaids
E Ugwuja, N Eze. A Comparative Study of Serum Electrolytes, Total Protein, Calcium and Phosphate Among Diabetic and HIV/AIDS Patients in Abakaliki, Southeastern, Nigeria. The Internet Journal of Laboratory Medicine. 2006 Volume 2 Number 1.
With high morbidity and mortality worldwide, diabetes mellitus and HIV/AIDS remain two clinical conditions of public health importance especially in developing countries [1, 2]. However, while HIV/AIDS is caused by human immunodeficiency virus (transmitted through sexual contact, contact with HIV-contaminated sharp objects, body fluids or from mother-to-child), diabetes mellitus may be of viral or genetic and/or environmental aetiology [3, 4].
Studies have shown that the incidence of diabetes has been on the increase in recent times with the introduction of highly active antiretroviral therapy (HAART) for the treatment of HIV/AIDS [5, 6]. It has been shown that HAART-use, especially the protease inhibitors (PI) among HIV/AIDS patients are associated with multiple complex metabolic alterations. Treatment of HIV/AIDS with PIs has been found to induce hyperlipidaemia and insulin resistance . Michael  has shown that new-onset diabetes mellitus, clinically similar to type 2 diabetes will affect about (1-6%) of patients infected with HIV and are receiving protease inhibitors. Additionally, treatments with protease inhibitors have been associated with high incidence of osteopenia and osteoporosis with mean serum calcium levels declining with HIV progression .
Patients with diabetes mellitus and HIV/AIDS show some similar clinical manifestations such as excessive sweat, diarrhoea, dysuria, tiredness and weight loss [3, 9]. Excessive sweat, diarrhoea and dysuria have been implicated in the abnormalities of electrolyte balance. Furthermore, HIV infection has been associated with renal disease (HIV- associated nephropathy), which is characterized, by nephritic-stage proteinuria (>3.5g/dl), azotaemia, hypoalbuminaemia and occasionally hypocalcaemia [10, 11, 12]. Electrolyte abnormalities and altered mineral metabolism which occur in patients with HIV/AIDS  have been found to contribute to bone diseases, cardiovascular diseases and other clinical problems .
With increase in life expectancy and alterations in lipid and mineral metabolism due to PI therapy, it is expected that diabetes mellitus and hypertension, which may consequently lead to secondary diabetic and hypertensive renal damage, will increase. This study which aims to provide baseline data for the differential diagnosis and effective management of HIV-infected patients who are at the risk of developing diabetes mellitus due to HAART-use will compare the plasma electrolytes, total protein, calcium and phosphate in diabetic and HIV infected Nigerians.
The purpose of the study was explained to both the patients and the volunteers after which informed consent were obtained.
The Ethical Committee of Ebonyi State University Teaching Hospital (EBSUTH), Abakaliki. approved the study protocol. The approval was on the agreement that patient anonymity must be maintained, good laboratory practice/quality control ensured, and that every finding would be treated with utmost confidentiality and for the purpose of this research only in compliance with the Helsinki declaration.
Sociodemographic data like age, sex, weight and height as well as duration of illness/infection and treatment details were obtained from case notes of the patients, while the controls were interviewed orally to obtain their age and sex. Weight (in Kg using a standard hospital balance) and height (in m using a metal rule) were measured (in light clothing, without shoes).
Materials And Methods
Five millilitres (5ml) venous blood was collected at 09.00hr every morning after overnight fast. The blood was dispensed into plane dry glass test tubes. Serums were isolated by centrifuging in a laboratory centrifuge at 2000g for three (3) minutes immediately after blood clotting and retraction at room temperature. The serums were refrigerated at 4 0 C.
Serum potassium (K + ), Sodium (Na + ) and Calcium (Ca ++ ) were analysed by Flame Atomic Absorption Spectrophotometer at the Department of Chemical Pathology, University of Nigeria Teaching Hospital (UNTH), Enugu.
Serum bicarbonate (HCO3 - ) was determined by titration in accordance with the method described by Van Slyke [
Serum chloride (Cl - ) was estimated by the mercuric nitrate colorimetric method described by Skeggs and Hochstrasser [
Serum Phosphate was determined spectrometrically as described by Garber and Miller [
Serum total protein was determined using method described by Reinhold [
19]. This is based on the ability of alkaline cupric solution to react with at least two peptide bonds to form a violet colour, which is estimated at 540nm. This colour development takes about fifteen (15) minutes.
Body mass index (BMI) was calculated using the formula: BMI = weight (kg)/height (m) 2 .
Student's t-tests were used to compare the groups for continuous data. Statistical significant was achieved if
Table 1 shows that diabetic patients were older and had longer duration of illness and higher BMI than either the controls or HIV/AIDS patients (p < 0.05).
Forty (40%) percent of the HIV/AIDS patients had AIDS. While HIVAIDS patients had comparable weight as the controls, the diabetics were overweight. Diabetic patients (mean glucose concentration = 8.7±0.5mmol/l) with poor glucose control (n=15) have various complications such as retinopathy (n=3), angiopathy (n=5), nephropathy (=4) and three (3) retinopathy and nephropathy (data not shown).
Table 2 compares serum electrolytes, total protein, calcium and phosphate in diabetes mellitus, HIV/AIDS and controls. Mean serum K + , Cl - , HCO3 - and PO4 3- were lower in diabetic and HIV/AIDS patients than in the controls and much lower in diabetics than in the HIV/AIDS (p < 0.05). Serum total protein was significantly lower in HIV/AIDS patients than in D/M and controls (62.90 ± 6.36g/l vs 66.19 ± 6.20 and 62.90 ± 6.3g/l vs 67.5 ± 6.4 respectively). However, serum calcium was not affected by either HIV/AIDS or diabetes mellitus. With the exception of K + , Ca ++ and PO4 3- all other parameters were significantly lower in HIV/AIDS patients not receiving HAART than in those on HAART treatment (table 3).
Expectedly D/M patients with poor glycaemic control had significantly higher fasting serum glucose than those with good glucose control. However, diabetic patients with poor glucose control had significantly lower levels of K +, Cl - and PO4 3- , which were lower than the reference range for K + but not for Cl - and PO4 3- than the diabetics with good glucose control. Serum Na + , Ca ++ and HCO3 - were not significantly affected by serum glucose levels (table 4). Table 5 shows the reference ranges of parameters analysed.
The significantly lower levels of some electrolytes (Na + , K + , HCO3 - , Cl - ,) as well as phosphate (PO4 3- ) observed in both diabetic and HIV/AIDS patients than in the controls in this study corroborate earlier study , though K + was within the reference range in HIV/AIDS patients and HCO3 - and PO4 3- in both HIV/AIDS and diabetics. Abnormalities in fluid and electrolytes balance are common biochemical findings in both HIV/AIDS and diabetes mellitus  and have been attributed to increased losses, reduced intake/absorption or alterations in metabolism [22, 23]. Malabsorption in HIV/AIDS patients accompanies frequent bout of diarrhoea due to gardia, cryptosporidium and other pathogens that affect persons with compromised immune systems. In addition to damage done to the intestinal epithelial cells, HIV-infected individuals have been found to have increased intestinal permeability and other intestinal defects even when asymptomatic . In diabetes mellitus, increased urinary loss due to osmotic diuresis may be the common and most important cause of reduced electrolytes, although intracellular shift (translocation) may also be a factor . More reduction in serum electrolytes in diabetic patients than people living with HIV/AIDS in this study is very curious and should be interpreted cautiously as study has shown that diarrhoea, which is common in people living with HIV/AIDS, is a common route for fluid and electrolyte loss . Significantly lower serum potassium in diabetics than in the controls is consistent with the role of blood glucose in potassium metabolism (high serum glucose enhances the movement of potassium from extracellular fluid into the cells). This role of glucose in K + metabolism was evidenced by significantly lower serum K + in diabetics with poor glucose control. Both elevated and depressed serum K + have been found to have profound effect on neurotransmission as well as cardiac functions [25,26]. The significantly lower mean value of chloride gave the same pattern as the level of Na + in diabetics because Na + is always (in most cases) in association with chloride. While calcium metabolism was affected by neither diabetes nor HIV/AIDS, HAART use in HIV/AIDS patients was associated with slightly higher mean serum calcium, which was statistically significant (2.1± 0.2 vs 2.3V± 0.3, p < 0.05), though still within the reference range (2.15-2.55mMol/l). This finding is in contrast with earlier finding by Kuehn and his co-workers  who reported lower mean serum calcium in HIV/AIDS patients than in controls.
In this study mean serum calcium was elevated within the reference range and may not be of any clinical relevance. Similarly, the significantly higher phosphate levels within the reference range in HIV/AIDS than in diabetes and in diabetics with poor glucose control than in diabetes with good glycaemic control (1.3 ± 0.4 vs 1.1 ± 0.2 and 1.1 ± 0.2 vs 1.0 ± 0.2 respectively) is in accord with the role of insulin in phosphate metabolism (insulin increases proximal phosphate reabsorption), and may not be of any clinical relevance. Curiously, mean serum HCO3 - and PO4 3- in the controls were close to the upper limit of the reference ranges (22-28mmol/l and 0.81-1.45mmol/l respectively) suggesting that significant number of them were hyperphopataemic or alkalotic. However non of the participants showed any sign of alkalosis or hyperphosphataemia suggesting that the observed high levels of PO4 3- and HCO3 - were characteristics of the study population and may be partly attributable to increased intake.
Significantly lower serum total protein in patients with HIV/AIDS than in diabetics and controls corroborates earlier finding . Although serum total protein estimation has limited diagnostic importance when compared to albumin because of the compensatory increases in other serum proteins (the globulins) during infections, its relevance in the evaluation of patients with some clinical conditions such as malnutrition, malignancy, renal and liver diseases and immune disorders cannot be ignored . Decrease in serum total protein in HIV infection has been associated with either increased losses and/or catabolism or as a result of reduction in intake and/or absorption due to sores in the mouth, pharynx and/or oesophagus, fatigue, depression and side effects of medications . However, HAART users were found to have significantly higher serum total protein than non-users (65.3 ± 6.9 vs 60.7 ± 5.6). It could therefore be conceived that HAART-use improves protein metabolism by improving the CD4 count , although it could not be established if the lower serum protein levels in HIV/AIDS patients in the present study were related to CD4 count. Reduced loss of protein in diarrhoea and catabolism in HAART users may also be a factor. However, with HIV progression protein loss may be more pronounced as it has been shown that about 0.6-1.2g of protein per kilogram body weight per day are lost in adults due to infection as a result of mobilisation of amino acids from skeletal muscles in response to the release of cytokines such as interleukin-1 (IL-1) and tumour necrosis factor-alpha (TNF-α) . These losses have been found to be highest in diarrhoea and dysentery, which are common in HIV infection.
The finding of mean serum total protein within the reference range in diabetics patients in this study should be interpreted with caution because our samples included diabetics on drugs as the possibility of glycaemic control having effect on protein metabolism cannot be completely ruled out. The normal serum total protein in diabetic patients as compared to significant decrease in HIV/AIDS patients suggest that protein losses in diabetics is lower, probably due to increased intakes and reduced losses through the gastrointestinal tract.
Although no literature on comparative study of serum electrolytes, total protein, calcium and phosphate in HIV/AIDS and diabetes mellitus was encountered, the results of this study show that diabetic patients experience greater electrolyte disturbances than persons living with HIV/AIDS. These findings need to be validated, as understanding the basic metabolic differences between the two conditions may have implications in the context of coexisting diabetes and HIV/AIDS in HIV/AIDS patients on HAART. However, we recommend strict monitoring of serum electrolytes in the two conditions as early detection and treatment of these abnormalities will enhance the quality of life of patients.
The authors are grateful to the staff and medical students of Ebonyi State University Teaching Hospital Abakaliki for their cooperation. We also thank the staff of Chemical Pathology Department of the University of Nigeria Teaching Hospital Enugu for their logistic support.
Ugwuja, E. I.
Department of Chemical Pathology, Faculty of Clinical Medicine, Ebonyi State University, Abakaliki, P.M.B 053, Nigeria.