title: Healthcare Fragmentation and the Frequency of Radiology and Other Diagnostic Tests: A Cross-Sectional Study.
abstract: BACKGROUND
  Fragmented ambulatory care has been associated with high rates of emergency department visits and hospitalizations, but effects on other types of utilization are unclear.
  
  
  OBJECTIVE
  To determine whether more fragmented care is associated with more radiology and other diagnostic tests, compared to less fragmented care.
  
  
  METHODS
  We conducted a cross-sectional study using claims from five commercial payers for 2010. The study took place in the Hudson Valley, a seven-county region in New York State.
  
  
  METHODS
  We included adult patients who were insured through the participating payers and were attributed to a primary care physician in the region. We restricted the cohort to those with ≥4 ambulatory visits, as measures of fragmentation are not reliable if based on ≤3 visits (N = 126,801).
  
  
  METHODS
  For each patient, we calculated fragmentation using a reversed Bice-Boxerman Index, which we divided into seven categories. We used negative binomial regression to determine the association between fragmentation category and rates of radiology and other diagnostic tests, stratified by number of chronic conditions and adjusting for patient age, gender, and number of visits.
  
  
  RESULTS
  Patients with the most fragmented care had approximately twice as many radiology and other diagnostic tests as patients with the least fragmented care, across all groups stratified by number of chronic conditions (each adjusted p < 0.0001). For example, among patients with ≥5 chronic conditions, those with the least fragmented care had 258 tests per 100 patients, and those with the most fragmented care had 542 tests per 100 patients (+284 tests per 100 patients, or +110 %, adjusted p < 0.0001).
  
  
  CONCLUSIONS
  More fragmented care was independently associated with higher rates of radiology and other diagnostic tests than less fragmented care.
authors: Division of General Internal Medicine, Department of Medicine, Weill Cornell Medicine, New York, NY, USA. lmk2003@med.cornell.edu.|Division of Health Policy and Economics, Department of Healthcare Policy & Research, Weill Cornell Medicine, New York, NY, USA. lmk2003@med.cornell.edu.
authors: Lisa M
authors: LM
authors: Kern
authors: Division of Health Policy and Economics, Department of Healthcare Policy & Research, Weill Cornell Medicine, New York, NY, USA.
authors: Joanna K
authors: JK
authors: Seirup
authors: Division of Health Policy and Economics, Department of Healthcare Policy & Research, Weill Cornell Medicine, New York, NY, USA.
authors: Lawrence P
authors: LP
authors: Casalino
authors: Division of General Internal Medicine, Department of Medicine, Weill Cornell Medicine, New York, NY, USA.
authors: Monika M
authors: MM
authors: Safford
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000553:Ambulatory Care / Q000706:statistics & numerical data*; D002908:Chronic Disease / Q000628:therapy*; D003430:Cross-Sectional Studies; D003695:Delivery of Health Care / Q000191:economics / Q000706:statistics & numerical data; D003955:Diagnostic Tests, Routine / Q000191:economics / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007348:Insurance, Health / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care / Q000191:economics / Q000458:organization & administration* / Q000706:statistics & numerical data
keywords: ambulatory care; healthcare utilization; radiology