The 'stone clinic effect': myth or reality?
Sixty-six active recurrent stone formers (RSF), i.e., with at least one stone annually over 3 years prior to the first examination at our stone clinic, were retrospectively evaluated. All received specific drug metaphylaxis which was discontinued after 5.5 +/- 2.1 years (period 1). They were reclassified according to the above definition into active and inactive RSF and were then left on a general metaphylactic regimen with regular urological follow-up every 6 months (period 2). 32 patients observed these recommendations for 5.7 +/- 2.6 years (group 1), 34 did not. 20 of these 34 could be reexamined after 6.3 +/- 2.2 years (group 2). Group 1 comprised 10 active and 22 inactive, group 2 comprised 1 active and 19 inactive RSF. While the recurrence rates among the inactive RSF of groups 1 and 2 decreased significantly during period 2, a statistically significant difference between them was not observed. Conversely, there was only a slight reduction of the recurrence rate in the active RSF. Both findings argue against a stone clinic effect. Interviews of the patients showed that stone formation was periodical for a mean of 12 +/- 8 years, after which it gradually faded out. This period is termed 'phase of regular stone formation' and appears to be an autonomous process that cannot usually be influenced by metaphylactic measures. This could explain the wide variability of reported success rates for the various metaphylactic regimens, as they would merely reflect the number of stone formers who are in their phase of regular stone formation.
Hofbauer
J
J
Department of Urology, University of Vienna, Austria.
Höbarth
K
K
Ludvik
G
G
Marberger
M
M
D000328:Adult; D000368:Aged; D000493:Allopurinol / Q000627:therapeutic use*; D001581:Benzothiadiazines; D002985:Clinical Protocols; D003131:Combined Modality Therapy; D004232:Diuretics; D004327:Drinking Behavior; D004359:Drug Therapy, Combination; D005247:Feeding Behavior; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012074:Remission Induction; D012189:Retrospective Studies; D049993:Sodium Chloride Symporter Inhibitors / Q000627:therapeutic use*; D013997:Time Factors; D014545:Urinary Calculi / Q000628:therapy*
D001581:Benzothiadiazines; D004232:Diuretics; D049993:Sodium Chloride Symporter Inhibitors; D000493:Allopurinol