title: One-stop clinic for ketamine-associated uropathy: report on service delivery model, patients' characteristics and non-invasive investigations at baseline by a cross-sectional study in a prospective cohort of 318 teenagers and young adults.
abstract: OBJECTIVE
  To describe a service delivery model and report the baseline characteristics of patients investigated by a non-invasive approach for ketamine-associated uropathy.
  
  
  METHODS
  This was a cross-sectional study in a prospective cohort of patients who attended their first visit and underwent non-invasive investigations at a dedicated centre to treat ketamine-associated uropathy in Hong Kong from December 2011 to July 2013. Data on demographics, illicit ketamine use, symptoms scores and voiding function parameters at baseline were prospectively collected. Differences between active abusers and ex-abusers, and risk factors for the most symptomatic group were investigated by univariate and multivariate analysis.
  
  
  RESULTS
  In all, 318 patients completed the non-invasive assessment at their first visit and were eligible for inclusion. In all, 174 were female and the mean (sd) age of the entire cohort was 24.4 (3.1) years. Patients had used ketamine for a mean (sd) period of 81 (36) months. The mean (sd) ketamine use per week was 18.5 (15.8) g. In all, 214 patients were active abusers while 104 were ex-abusers but had persistent lower urinary tract symptoms. The mean (sd) voided volume, bladder capacity, and bladder emptying efficiency were 111.5 (110) mL, 152.5 (126) mL and 73.3 (26.9)%, respectively. The ex-abusers had a lower symptom score (19.3 vs 24.1; P < 0.001), a larger voided volume (126 vs 85 mL; P < 0.001), and a larger bladder capacity (204.8 vs 126.7 mL; P < 0.001) compared with active abusers. Multivariate analysis found female gender was associated with a higher symptom score (odds ratio [OR] 2.39; 95% confidence interval [CI] 1.35-4.23; P = 0.003) and a smaller voided volume (OR 1.9; 95% CI 1.1-3.3; P = 0.02). Ketamine taken (g/week) was another risk factor for a higher symptom score (OR 1.03; 95% CI 1.01-1.05; P = 0.002). Status of ex-abuser was the only protective factor associated with fewer symptoms, larger voided volume and bladder capacity.
  
  
  CONCLUSIONS
  An effective service model for recruiting patients with ketamine-associated uropathy is possible. With such a service model as a platform, further prospective studies are warranted to investigate the appropriate choice of treatment for this new clinical entity.
authors.affiliation: Department of Surgery, Youth Urological Treatment Centre, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Yuk-Him
authors.initials: YH
authors.lastname: Tam
authors.forename: Chi-Fai
authors.initials: CF
authors.lastname: Ng
authors.forename: Kristine Kit-Yi
authors.initials: KK
authors.lastname: Pang
authors.forename: Chi-Hang
authors.initials: CH
authors.lastname: Yee
authors.forename: Winnie Chiu-Wing
authors.initials: WC
authors.lastname: Chu
authors.forename: Vivian Yee-Fong
authors.initials: VY
authors.lastname: Leung
authors.forename: Grace Lai-Hung
authors.initials: GL
authors.lastname: Wong
authors.forename: Vincent Wai-Sun
authors.initials: VW
authors.lastname: Wong
authors.forename: Henry Lik-Yuen
authors.initials: HL
authors.lastname: Chan
authors.forename: Paul Bo-San
authors.initials: PB
authors.lastname: Lai
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D003430:Cross-Sectional Studies; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D013287:Illicit Drugs / Q000506:poisoning*; D007649:Ketamine / Q000506:poisoning*; D008297:Male; D017699:Pelvic Pain / Q000139:chemically induced* / Q000453:epidemiology; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000209:etiology*; D014570:Urologic Diseases / Q000139:chemically induced* / Q000453:epidemiology; D055815:Young Adult
chemical_list: D013287:Illicit Drugs; D007649:Ketamine
keywords: ketamine; ketamine-associated cystitis; ketamine-associated uropathy; lower urinary tract symptoms (LUTS)