Hyperhomocysteinemia and related factors in 600 hospitalized elderly subjects

Hyperhomocysteinemia (HHcy) is a metabolic disorder frequently occurring in the elderly population. Recently several reports have suggested abnormalit ies in homocysteine (tHcy) metabolism implicating HHcy as a metabolic link in the multifactorial processes characterizing many geriatric illnesses-wit h special emphasis on atherosclerotic vascular diseases and cognitive impai rment. The present study was undertaken in a large sample of elderly hospit alized subjects to determine (1) the prevalence of HHcy, (2) the associatio n of HHcy with vascular and cognitive disorders, and (3) the factors indepe ndently predicting Hhcy. Six hundred elderly subjects (264 men and 336 wome n; mean age, 79 +/-9 years) were randomly chosen from those admitted as inp atients over a period of 3 years. In all patients, body mass index (BMI), m id-upper arm muscle area (MUAMA), plasma cholesterol, triglycerides, total proteins, albumin, lymphocyte count, creatinine, homocysteine (fasting and 4 hours after methionine oral load), serum vitamin B-6, vitamin B-12, and f olate concentrations were measured. The presence of disease or use of medic ations known to affect homocysteine plasma levels were also recorded. The m ean fasting tHcy level was 16.8 +/- 12 mu mol/L in the whole sample, 18.18 +/- 13.25 mu mol/L in men, and 15.86 +/- 12.14 mu mol/L in women (P=.005 me n v women). The mean Hcy level 4 hours after methionine load was 37.95 +/- 20.9 in the whole sample. Prevalence of hyperhomocysteinemia (fasting Hcy g reater than or equal to 15 mu mol/L or 4 hours after methionine load greate r than or equal to 35 mu mol/L) was 61% (365/600) (67% in men and 56% in wo men, P<.05). HHcy was rarely (8%) an isolated disorder; in addition to diab etes (20%), renal failure (48.2%), and malnutrition (20.2%), it was often a ssociated with heart failure (30%), malignancies (20.5%), and the use of di uretics (56%) and anticonvulsant drugs (13%). Plasma homocysteine progressi vely increases across subjects from those with no diabetes, malnutrition, r enal failure, obesity, inflammatory bowel disease, heart failure to those w ith 1, 2, or more concurrent diseases. Multiple stepwise regression analysi s showed that 72% of plasma total fasting tHcy variability was explained by age, serum folate, plasma albumin, use of diuretics, and renal function (m easured as plasma creatinine clearance). In conclusion, the present study d ocuments that hyperhomocysteinemia, in elderly hospitalized patients is (1) a common finding, (2) frequently associated with vascular and cognitive di sorders, and (3) probably a secondary phenomenon in most cases. The major p redictor of high plasma homocysteine levels were age, serum folate, plasma albumin, plasma creatinine clearance, and use of diuretic drugs. These vari ables explain a large proportion of plasma Hcy variability. Copyright (C) 2 001 by W.B. Saunders Company.