In this cross-sectional study, 160 haemodialysis patients with mean age (± SD) 52.2(13.3) years were recruited to determine the prevalence of Malnutrition Inflammation Complex Syndrome and its associated factors at MNH in Dar es Salaam, Tanzania. More than two-third of the patients, 111 (69.4%) were male and the majority 132 (82.5%) were on HD three times per week (as per KDOQI recommendations). The prevalence of MICS was 46.3% and based on severity; MICS was categorized as mild in 24.4% and moderate to severe in 21.9% of the patients. In multivariate analysis, longer duration on HD (> 4 years) was a significant predictor of MICS and hypercholesterolaemia was a negative predictor of MICS. Patients with MICS had significantly lower mean BMI, albumin, total cholesterol, transferrin, haemoglobin and creatinine levels.
A lower prevalence of MICS was noted in this study as compared to 61.2% reported by Matiko in a study conducted among HD patients in Kenya [7]. This difference could be attributed to adequacy of dialysis as indicated by lower frequency (two times weekly) of dialysis in the study by Matiko as compared to our study in which most patients were getting three times per week dialysis. [7]. Inadequate dialysis can lead to persistently high urea levels, subsequent inflammation and protein catabolism [8]. However, in this study, dialysis adequacy and URR did not associate with MICS. Moderate to severe MICS was noted in 21.9% of HD patients in this study, which is similar to a report from South Africa that was reported to be 22% [15].
Malnutrition was prevalent in 16.9% of the patients; this was higher than prevalence of 9.8% reported by Somji et al in a study conducted in Dar es Salaam, Tanzania among patients on HD therapy [16]. The prevalence of malnutrition found in our study was lower when compared to other studies in African countries; 20.9% in Kenya [7], 29.2% in Niger [17] and 28.3% in Cameroon [18]. Patients with MICS have varying degrees of muscle wasting [8, 12]. In this study, patients with MICS had a mean BMI of 20.2 ± 2.7 kg/m2 and almost half (48.4%) of the patients with normal BMI had MICS, this implies that relying on BMI alone for nutritional assessment may not be accurate in these patients. The Malnutrition Inflammation Score is a better tool in assessment of nutritional status of HD patients and have been found to better correlate with morbidity, quality of life and mortality [3, 5, 6]. Several factors affect the nutritional status of HD patients; decreased calorie intake, inadequate dialysis, metabolic acidosis, persistent inflammation and HD related catabolism [4, 8]. In this study, almost a half of the patients had reported some deterioration in dietary intake and almost a third of patients reported gastrointestinal symptoms that may limit adequate dietary intake.
In our study, inflammation was present in 81.6% of the patients; this was lower than that found in the study done in Kenya where by all patients had raised CRP [7]. Inflammation in patients on HD is common and largely attributed to persistent uremia. There are multiple other triggers including HD procedure itself, dialysate quality and bio-incompatibility of dialysis membranes [4, 9]. The median CRP in our study was significantly higher in patients with MICS; this was similar to a study done in Mexico [19].
In this study, patients on HD for longer duration (> 4 years) had 5 times odds of having MICS compared to those on HD for less than 4 years. This finding is consistent with findings from a study by Omari et al who reported long duration of dialysis to be linked with malnutrition inflammatory syndrome in Palestine [20]. Longer duration on HD therapy result in prolonged exposure of patients to negative effects of HD including dialysis related inflammation, loss of nutrients and increased energy expenditure that subsequently can result into malnutrition [8]. This highlights the need for efforts of increasing uptake of HD patients into kidney transplantation program to limit the time spent of chronic HD therapy.
Age has been reported to correlate with MICS did not show this effect in our study, and this might be attributed to younger age of participants in this study with mean age of 52 years. In a study conducted by Rambod et al among dialysis patients in America, older patients were noted to be having significantly higher burden of MICS [5]. MICS among older patients is attributed largely to co-morbidities including depression that affects the dietary intake of these patients.
In this study, the mean total cholesterol level was significantly lower in patients with MICS, which is contrary to a report by Valencia et al that reported no difference in cholesterol levels between dialysis patients with and without MICS in Mexico [19]. Cholesterol is an important nutritional biomarker among patients on HD therapy and hypercholesterolaemia may be protective in these patients unlike the general population [21, 22].
Mean albumin level was noted to be significantly lower among patients with MICS; this was an expected finding, which is consistent with reports from other similar studies [5, 6]. Albumin is a good indicator of protein energy malnutrition for patients with chronic renal failure; hypoalbuminaemia is attributed to visceral protein loss among patients undergoing haemodialysis as well as peritoneal dialysis [8].
Serum creatinine levels have been reported to be lower among HD patients and patients with MICS have also been noted to have lower mean pre and post dialysis creatinine levels [6, 19]. The phenomenon of hypocholesterolaemia and hypocreatininaemia among patients on chronic dialysis, accompanied with MICS is referred to as ‘reverse epidemiology’. Reverse epidemiology is paradoxically associated with poor cardiovascular outcomes [21, 22], therefore health care providers providing chronic dialysis therapy should be vigilant and monitor these markers regularly to improve outcome of chronic dialysis.
Strengths and Limitations
This is the first study in Tanzania to explore the burden of malnutrition and inflammation in HD patients. The other strength of this study was that it also assessed the relationship between nutritional and inflammatory biomarkers with MICS and were shown to be correlated hence reinforces the need for synergistic assessment of these parameters. One limitation in this study was the inter-observer bias while measuring the fat and muscle loss. Systemic errors during measurement of anthropometric indices could have occurred. There might be some selection bias from exclusion of a small group of very sick and mentally debilitated patients. This may underestimate the outcome. Another limitation was that the CRP test was not done for all patients; this was due to financial restrictions and other logistic challenges.