EFFECTIVENESS OF MEDICAL NUTRITION THERAPY PROVIDED BY DIETITIANS IN THE MANAGEMENT OF NON-INSULIN-DEPENDENT DIABETES-MELLITUS - A RANDOMIZED, CONTROLLED CLINICAL-TRIAL

Objective To assess the effect of medical nutrition therapy (MNT) prov ided by dietitians on medical and clinical outcomes for adults with no n-insulin-dependent diabetes mellitus (NIDDM), and to compare MNT admi nistered according to practice guidelines nutrition care (PGC) to MNT administered with basic nutrition care (BC). Design A prospective, ran domized, controlled clinical trial of two levels of MNT on metabolic c ontrol in persons newly diagnosed with or currently under treatment fo r NIDDM was conducted at diabetes centers in three states (Minnesota, Florida, and Colorado). BC consisted of a single visit with a dietitia n; PGC involved an initial visit with a dietitian followed by two visi ts during the first 6 weeks of the study period. Data were collected a t entry to the study and at 3 and 6 months. Subjects Results are repor ted for 179 men and women aged 38 to 76 years: 85 assigned randomly to BC and 94 to PGC. This represents 72% of the 247 subjects enrolled. A n additional 62 adults with NIDDM at one site who had no contact with a dietitian were identified as a nonrandom comparison group. Outcomes Medical outcome measures included fasting plasma glucose (FPG), glycat ed hemoglobin (HbA(1c)), and serum lipid levels. Clinical outcomes inc luded weight, body mass index, waist-to-hip ratio, and changes in medi cal therapy. Statistical analyses Initial analysis of the discrete var iables was done using the chi(2) statistic with Yates' correction. Ini tial analysis of continuous variables was done by analysis of variance . The changes in variables between time periods were analyzed by paire d t test, and comparisons between groups were analyzed using a t test for independent groups. Results At 6 months, PGC resulted in significa nt improvements in blood glucose control as indicated by FPG and HbA(1 c) levels and BC resulted in significant improvements in HbA(1c) level . Participants assigned to the PGC group had a mean FPG level at 6 mon ths that was 10.5% lower than the level at entry, and those in the BC group had a 5.3% lower value. Among subjects who had diabetes for long er than 6 months, those who received PGC had a significantly better Hb A(1c) level at 3 months compared with those receiving BC. The comparis on group showed no improvement in glycemic control over a comparable 6 months. PGC subjects had significant improvements in cholesterol valu es at B months, and subjects in both the PGC and the BC groups had sig nificant weight loss. Conclusions MNT provided by dietitians resulted in significant improvements in medical and clinical outcomes in both t he BC and PGC groups and is beneficial to persons with NIDDM. Persons with a duration of diabetes longer than 6 months tended to do better w ith PGC than with BC. Because of the upward trend in glucose levels af ter 3 months, ongoing MNT by dietitians is important for long-term met abolic control.