title: Long-term effect of coffee consumption on autosomal dominant polycystic kidneys disease progression: results from the Suisse ADPKD, a Prospective Longitudinal Cohort Study.
abstract: Previous in vitro experiments of human polycystic kidney disease (PKD) cells reported that caffeine is a risk factor for the promotion of cyst enlargement in patients with autosomal dominant PKD (ADPKD). The relentless progression of ADPKD inclines the majority of physicians to advocate minimization of caffeine consumption despite the absence of clinical data supporting such a recommendation so far. This is the first clinical study to assess prospectively the association between coffee consumption and disease progression in a longitudinal ADPKD cohort.
  
  
  
  Information on coffee consumption and disease progression was collected at each follow-up visit using standardized measurement methods. The main model for the outcomes, kidney size (height-adjusted total kidney volume, htTKV) and kidney function (estimated glomerular filtration rate, eGFR), was a linear mixed model. Patients entered the on-going Swiss ADPKD study between 2006 and June 2014 and had at least 1 visit every year. The sample size of the study population was 151 with a median follow-up of 4 visits per patient and a median follow-up time of 4.38 years.
  
  
  
  After multivariate adjustment for age, smoking, hypertension, sex, body mass index and an interaction term (coffee*visit), coffee drinkers did not have a statistically significantly different kidney size compared to non-coffee drinkers (difference of -33.03 cm3height adjusted TKV, 95% confidence interval (CI) from -72.41 to 6.34, p = 0.10). After the same adjustment, there was no statistically significant difference in eGFR between coffee and non-coffee drinkers (2.03 ml/min/1.73 m2, 95% CI from -0.31 to 4.31, p = 0.089).
  
  
  
  Data derived from our prospective longitudinal study do not confirm that drinking coffee is a risk factor for ADPKD progression.
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, 8001, Zurich, Switzerland. laura.girardat-rotar@uzh.ch.
authors.forename: Laura
authors.identifier: http://orcid.org/0000-0002-1717-0976
authors.initials: L
authors.lastname: Girardat-Rotar
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, 8001, Zurich, Switzerland.
authors.forename: Milo A
authors.initials: MA
authors.lastname: Puhan
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, 8001, Zurich, Switzerland.
authors.forename: Julia
authors.initials: J
authors.lastname: Braun
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, 8001, Zurich, Switzerland.|Department of Internal Medicine and Nephrology, Medizinisches Kompetenzzentrum für ADPKD, Suisse ADPKD, Hirslanden, Zurich, Switzerland.
authors.forename: Andreas L
authors.initials: AL
authors.lastname: Serra
mesh_terms: D000328:Adult; D003069:Coffee / Q000009:adverse effects; D018450:Disease Progression; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D016891:Polycystic Kidney, Autosomal Dominant / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013557:Switzerland / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult
chemical_list: D003069:Coffee
keywords: ADPKD; Coffee; Epidemiology; Kidney volume; Progression; Renal function decline