ON THE PROGNOSIS OF IDDM PATIENTS WITH LARGE KIDNEYS

Background. Approximately 10-30% of IDDM patients develop diabetic nep hropathy depending on the metabolic control. Previous examinations on the significance of the kidney size prior to the manifestation of neph ropathy produced varying results. Methods. The present study, therefor e, was designed to assess the correlation between sonographically dete rmined kidney size and kidney function over 8 years in a follow-up exa mination, and to evaluate a potential risk pattern. Data could be coll ected from 73 (66%) of 110 IDDM patients with initially normal serum c reatinine whose sonographically determined kidney volume (cm(3) = L cm x W cm x D cm x pi/6) and kidney function (creatinine, albuminuria, b eta(2)-microglobulin in serum) had been examined in 1986, and who had a diabetes duration of 1 month to 25 years at that time. Results. 30% (11 of 37) patients with large kidneys (>170 cm(3)) reached at least o ne serious renal endpoint (increase of serum creatinine by more than 5 0%, requirement of dialysis or kidney transplantation, or death in end -stage renal disease) versus one of 36 patients with normal kidney siz e (P<0.002). As many as 42% of patients with large kidneys developed a bnormal creatinine values (>106 mu mol/l) in contrast to only 20% of t he patients with normal kidney volume (P<0.05). Six of seven patients with a more than 50% increase of serum creatinine from baseline showed large kidneys in 1986, but had a normal serum creatinine, and four al so a normal urine albumin excretion. Furthermore all five patients wit h more severe endpoints (two deaths in end stage renal disease and thr ee patients presently requiring dialysis) exhibited either an increase d serum creatinine or large kidneys at baseline; four of these, howeve r, were still in the normoalbuminuric state in 1986. Conclusions. Thes e results indicate that large kidneys might be a morphological marker for subsequent diabetic nephropathy, and as a consequence, renal insuf ficiency.