Hyperphosphatemia among end-stage renal disease patients in developing countries: a forgotten issue?

The prevalence of hyperphosphatemia and increased calcium-phosphorus product has never been evaluated in a large multicenter study in a developing country. Our aim is to study the prevalence of hyperphosphatemia in 38 HD centers in Egypt (as an example of a developing country) and to correlate it with different co-morbid conditions and the patient's demographic data. This is a cross-sectional study conducted on 1005 chronic kidney disease stage 5 patients (CKD-stage 5) on HD for a period of more than 1 year in 38 dialysis centers in Egypt. All patients were receiving calcium-based salts as a phosphate binder. Hyperphosphatemia and increased calcium-phosphorus product were evaluated and correlated with different parameters including age, sex, knowledge by diet parameters, HD session duration, the frequency of HD per week, the type of dialysis membrane, the surface area of the dialyzer, dialyzer phosphorus clearance (phosphorus KoA), and the type of dialysate. Other co-morbid medical conditions and evidence of IHD were also investigated. Hyperphosphatemia was present in 69.1% of cases and a high calcium-phosphorus product was present in 30.2%. A higher calcium-phosphorus product was found among males. 83.2% of those with a poor knowledge by diet parameters had hyperphosphatemia compared with 67.6% in patients with a satisfactory knowledge by diet parameters. 72.3% of patients using a membrane with low-to-medium clearance had hyperphosphatemia, compared with 67.2% using a membrane with a high clearance. Seventy-two percent of patients with IHD were hyperphosphatemic compared with 67.6% of the non-ischemic patients. Hyperphosphatemia is a major problem in dialysis patients in developing countries, reflecting differences from developed countries regarding dietary habits, ethnic factors, dialysis quality, types of dialysis membranes, as well as economic factors hampering the use of the more expensive phosphate binders. Extended dialysis hours may be a good alternative solution in developing countries.