上部尿路結石症に対する内視鏡的治療後の結石の再発,増大に関する統計学的研究 : 多変量解析による再発,増大因子の検討  [in Japanese] LONG-TERM RESULTS OF ENDOUROLOGICAL TREATMENT OF URINARY CALCULI : Multivariate Analyses of the Risk Factors Related to Recurrence or Re-Growth  [in Japanese]

上部尿路結石症の再発や残石の増大に関与する因子を評価するため,endourologyで治療した167腎単位を対象に,単変量解析法と多変量解析法を用いて統計学的に検討した.167腎単位中,再発は28腎単位(17%)に,増大は16腎単位(10%)に見られた.また全再発の71%,全増大の81%が術後3カ月から2年以内の早期に発生した.単変量解析法での検討では,いずれの因子間にも有意差を認めなかった.一方,多変量解析法での検討は,Coxの比例ハザードモデルでは腎盂腎杯結石,大きさ20mm以上,PNL,尿路結石の既往あり,大きさ10mmから20mm,2個以上の6変数が有意に再発,増大に関与し,段階的選択で腎盂腎杯結石,尿路結石の既往あり,UPJおよび上部尿管結石の3変数が促進因子,大きさ10mmから20mmが抑制因子として選ばれた.ロジスティック回帰分析では尿路結石の既往あり,治療不成功,腎盂腎杯結石,2個以上の4変数が有意に再発,増大に関与し,段階的選択で尿路結石の既往あり,PNL,治療不成功の3変数が促進因子,61歳以上が抑制因子として選ばれた.以上の解析結果から尿路結石の既往あり,腎盂腎杯結石,2個以上の3変数が再発,増大の危険因子と判明した.中でも尿路結石の既往ありは両解析ともに段階的に選択された唯一の危険因子であり,再発症例には結石の完全除去のみならず再発予防療法を含む注意深い経過観察が必要と考えられた.

To evaluate the risk factors related to the long-term outcome of endourologic treatment of urinary calculi, data from the rates of recurrence or re-growth in 145 patients with 167 renal units who were observed for more than 3 months at the Hiroshima University Hospital, were reviewed. The factors included in the present analysis were age, previous stone, location, number, size and composition of stone and procedures of treatment. Of 167 renal units, the overall recurrence and re-growth rates were 17% and 10%, respectively. The earliest recurrence and re-growth appeared at 3 months after the treatment, and 71%o of recurrence and 81% of re-growth occurred within 2 years. In 9 out of 20 renal units (45%) with unsuccessful treatment, residual stones enlarged during the follow-up. Stone located in renal calyx and pelvis, previous stone, multiple stones, size of stone more than 20 mm, stone composed of calcium oxalate and/or calcium phosphate and struvite stone were likely to be risk factors. However, on the univariate analysis there were no significance of difference among these variables. On the results of analysis by Cox's proportional hazards model, characteristics such as stone located in renal calyx and pelvis, size of stone more than 20 mm (p<0.01), treatment with percutaneous nephrolithotripsy (PNL), previous stone, size of stone between 10 mm and 20 mm, and multiple stones (p<0.05), were significantly related to either recurrence or re-growth of stone. Four variables, stone located in renal calyx and pelvis, previous stone, upper ureteral and UPJ stone, and size of stone between 10 mm and 20 mm, were entered by stepwise selection, resulting that the last one was an inhibitory factor and the others were promoting factors. Logistic regression analysis also showed that previous stone, unsuccessful treatment, stone located in renal calyx and pelvis, and multiple stones were significantly related to either recurrence or re-growth (p<0.05). Results obtained by the stepwise selection demonstrated that 3 variables, previous stone, treatment with PNL and unsuccessful treatment, were promoting factors and one variable, age more than 61-year-old, was an inhibitory factor. On the prediction of recurrence or re-growth using above 4 variables, the correct diagnosis was 67.0%. Both analyses by Cox's proportional hazards model and logistic regression analysis indicated that chalacteristics such as previous stone, stone located in renal calyx and pelvis, and multiple stones were significantly correlated with recurrence or re-growth of stone. In these variables, previous stone was the most important risk factor. These results indicate that periodical checkup including a preventive procedures is mandatory in a high risk patient.