title: A comparison of SF-36 and SF-12 composite scores and subsequent hospitalization and mortality risks in long-term dialysis patients.
abstract: OBJECTIVE
  The Short Form 12 (SF-12) has not been validated for long-term dialysis patients. The study compared physical and mental component summary (PCS/MCS) scores from the SF-36 with those from the embedded SF-12 in a national cohort of dialysis patients.
  
  
  METHODS
  All 44,395 patients who had scorable SF-36 and SF-12 from January 1, 2006, to December 31, 2006, and were treated at Fresenius Medical Care, North America facilities were included. Death and first hospitalization were followed for up to 1 year from the date of survey. Correlation and agreement were obtained between PCS-36 and PCS-12 and MCS-36 and MCS-12; then Cox models were constructed to compare associated hazard ratios (HRs) between them.
  
  
  RESULTS
  Physical and mental dimensions both exhibited excellent intraclass correlation coefficients of 0.94. Each incremental point for both PCS-12 and PCS-36 was associated with a 2.4% lower adjusted HR of death and 0.4% decline in HR for first hospitalization (both P < 0.0001). Corresponding improvement in HR of death for each MCS point was 1.2% for MCS-12 and 1.3% for MCS-36, whereas both had similar 0.6% lower HR for hospitalization per point (all P < 0.0001).
  
  
  CONCLUSIONS
  The use of the SF-12 alone or as part of a larger survey is valid in dialysis patients. Composite scores from the SF-12 and SF-36 have similar prognostic association with death and hospitalization risk. Prospective longitudinal studies of SF-12 surveys that consider responsiveness to specific clinical, situational, and interventional changes are needed in this population.
authors.affiliation: Clinical Sciences, Epidemiology, and Research, Fresenius Medical Care, North America, Waltham, Massachusetts 02451-1457, USA. elacsonj@fmc-na.com
authors.forename: Eduardo
authors.initials: E
authors.lastname: Lacson
authors.forename: Jianglin
authors.initials: J
authors.lastname: Xu
authors.forename: Shu-Fang
authors.initials: SF
authors.lastname: Lin
authors.forename: Sandie Guerra
authors.initials: SG
authors.lastname: Dean
authors.forename: J Michael
authors.initials: JM
authors.lastname: Lazarus
authors.forename: Raymond M
authors.initials: RM
authors.lastname: Hakim
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D019538:Health Care Surveys; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications / Q000175:diagnosis* / Q000401:mortality* / Q000628:therapy*; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D006435:Renal Dialysis / Q000009:adverse effects / Q000401:mortality*; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome