title: Clinical features of kidney cancer in primary care: a case-control study using primary care records.
abstract: BACKGROUND
  Kidney cancer accounts for over 4000 UK deaths annually, and is one of the cancer sites with a poor mortality record compared with Europe.
  
  
  OBJECTIVE
  To identify and quantify all clinical features of kidney cancer in primary care.
  
  
  METHODS
  Case-control study, using General Practice Research Database records.
  
  
  METHODS
  A total of 3149 patients aged ≥40 years, diagnosed with kidney cancer between 2000 and 2009, and 14 091 age, sex and practice-matched controls, were selected. Clinical features associated with kidney cancer were identified, and analysed using conditional logistic regression. Positive predictive values for features of kidney cancer were estimated.
  
  
  RESULTS
  Cases consulted more frequently than controls in the year before diagnosis: median 16 consultations (interquartile range 10-25) versus 8 (4-15): P<0.001. Fifteen features were independently associated with kidney cancer: visible haematuria, odds ratio 37 (95% confidence interval [CI] = 28 to 49), abdominal pain 2.8 (95% CI = 2.4 to 3.4), microcytosis 2.6 (95% CI = 1.9 to 3.4), raised inflammatory markers 2.4 (95% CI = 2.1 to 2.8), thrombocytosis 2.2 (95% CI = 1.7 to 2.7), low haemoglobin 1.9 (95% CI = 1.6 to 2.2), urinary tract infection 1.8 (95% CI = 1.5 to 2.1), nausea 1.8 (95% CI = 1.4 to 2.3), raised creatinine 1.7 (95% CI = 1.5 to 2.0), leukocytosis 1.5 (95% CI = 1.2 to 1.9), fatigue 1.5 (95% CI = 1.2 to 1.9), constipation 1.4 (95% CI = 1.1 to 1.7), back pain 1.4 (95% CI = 1.2 to 1.7), abnormal liver function 1.3 (95% CI = 1.2 to 1.5), and raised blood sugar 1.2 (95% CI = 1.1 to 1.4). The positive predictive value for visible haematuria in patients aged ≥60 years was 1.0% (95% CI = 0.8 to 1.3).
  
  
  CONCLUSIONS
  Visible haematuria is the commonest and most powerful single predictor of kidney cancer, and the risk rises when additional symptoms are present. When considered alongside the risk of bladder cancer, the overall risk of urinary tract cancer from haematuria warrants referral.
authors.affiliation: University of Exeter Medical School, Exeter, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Shephard
authors.forename: Richard
authors.initials: R
authors.lastname: Neal
authors.forename: Peter
authors.initials: P
authors.lastname: Rose
authors.forename: Fiona
authors.initials: F
authors.lastname: Walter
authors.forename: William T
authors.initials: WT
authors.lastname: Hamilton
mesh_terms: D015746:Abdominal Pain / Q000453:epidemiology*; D000368:Aged; D001416:Back Pain; D016022:Case-Control Studies; D005260:Female; D058006:General Practice; D006417:Hematuria / Q000453:epidemiology*; D006801:Humans; D007249:Inflammation / Q000453:epidemiology*; D007680:Kidney Neoplasms / Q000150:complications* / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D009325:Nausea / Q000453:epidemiology*; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011320:Primary Health Care; D012017:Referral and Consultation; D006113:United Kingdom / Q000453:epidemiology; D014552:Urinary Tract Infections / Q000453:epidemiology*
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