title: Does comorbid disease influence consultation for knee problems in primary care?
abstract: OBJECTIVE
  Knee pain affects 25% of the population aged over 55 years and is the most common complaint of pain among those consulting for primary care. However, a large proportion do not seek help, with up to 50% of those with the most severe form of pain not consulting. Little is known about why this appears to be happening. Our aim was to examine whether consultations for concurrent comorbid disease had any influence on an individual's likelihood of consulting for knee-related problems in primary care.
  
  
  METHODS
  This was a case-crossover control study of patients aged over 50 years from three North Staffordshire practices with knee pain followed over a three-year period. All comorbid consultations for the same period were identified. The date of knee consultation cases were identified, and within-subject control days for the same individual were determined for 12 months previously or later where there was no knee consultation. McNemar's test for matched pairs was then carried out to assess whether consultation for either a chronic or acute condition in the preceding three months was associated with knee consultation.
  
  
  RESULTS
  A total of 281 participants were included in the case-crossover analysis. There was a lower frequency of chronic comorbid consultations in the three months preceding knee consultation than in either the previous (OR = 0.30; 95% CI 0.11, 0.74) or later control windows (OR = 0.56; 95% CI 0.27, 1.09). There was no difference in the frequency of acute comorbid consultations.
  
  
  RESULTS
  This study suggests that consultations for knee problems are preceded by a period of relatively fewer consultations for other chronic comorbid conditions. Patients might choose to consult for their knee problem when comorbid issues are not a priority. Future research might investigate whether certain comorbid conditions have a greater effect than others, and whether a proactive approach such as screening for knee disorders might improve prognosis?
authors.affiliation: Arthritis Research Campaign National Primary Care Centre, Primary Care Sciences, Keele University, Staffordshire, UK. j.bedson@cphc.keele.ac.uk
authors.forename: John
authors.initials: J
authors.lastname: Bedson
authors.forename: Umesh
authors.initials: U
authors.lastname: Kadam
authors.forename: Sara
authors.initials: S
authors.lastname: Muller
authors.forename: George
authors.initials: G
authors.lastname: Peat
mesh_terms: D000208:Acute Disease; D000367:Age Factors; D018771:Arthralgia / Q000175:diagnosis*; D002908:Chronic Disease; D015897:Comorbidity; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010147:Pain Measurement; D011320:Primary Health Care / Q000379:methods*; D011379:Prognosis; D012017:Referral and Consultation; D018570:Risk Assessment; D006113:United Kingdom