Socio-economic factors, food habits and phosphorus levels in patients on hemodialysis

BACKGROUND: Hyperphosphoremia is one of the most important risk factors for morbidity and mortality for chronic kidney disease (CKD) patients, and also, for the general population. Excessive dietary intake of phosphate (P) is one of the key factors. In particular, P in its inorganic form, which is contained in food additives, is more readily absorbed. Unfortunately, these food additives are mostly present in convenience so called "fast foods" (pre-cooked), soft drinks, which represent the typical food consumed by our hemodialysis (HD) population, composed by elderly people, mostly low-socio economic class, who often live alone. OBJECTIVES: We performed an observational retrospective multicenter study to find any association between social, cultural and economic situation, as well as food habits, and P levels in a cohort of patients on HD. Secondarily; we also examined the association between the fast food consumption and increased P levels, as well as patient compliance for P binding products. PATIENTS AND METHODS: To explore the association between socio-economic factors and serum P levels, we enrolled 100 patients on periodic HD treatment from three different units. Information on social, cultural, economic, diet habits, therapy for hyperphosphoremia and hematological and clinical parameters had been collected through specific questionnaires, administered by a physician. RESULTS: Results showed serum P level was reduced in patients who live alone compared to patients in family (P = 0.04), in self-sufficient (P = 0.05) and in patients belonging to middle-upper class, versus low-class (P = 0.003). Fast foods intake correlates with increase in P serum levels (P = 0.002), whilst the same correlation was not found for cheese intake. Our data show that socio-economic status and food habits are useful predictors of P serum levels. CONCLUSIONS: In conclusion, dietary counseling of patients on HD is mandatory. Interventions that consider the socio-economic situation allow delivering important messages on foods with the least amount of P and adequate protein content, and they may be a successful strategy in targeting patients at a higher risk of hyperphosphoremia.