Correlated measures in longitudinal analysis of daily drug use patterns in a general intensive care unit.
OBJECTIVE
The objective of the present study is to compare two different study designs (with and without corrections for correlated measures) to identify possible determinants of psychotropic drug use in an intensive care unit (ICU).


METHODS
In a logistic regression analysis, odds ratios (OR) were calculated for days in which patients were exposed to psychotropics compared with non-exposed days. In order to adjust for correlated measures, logistic regression with a logistic binomial model was applied.


RESULTS
We found that adjustment for correlated measures did not result in major changes in the OR. However, with more observations per patient parameter, adjustment for correlation has greater effect.


CONCLUSIONS
Adjustment for correlated measures may be useful in longitudinal drug analyses.
Stolker
Joost J
JJ
Altrecht Institute for Mental Health Care, Den Dolder, The Netherlands. j.stolker@altrecht.nl
Heerdink
Eibert R
ER
Zitman
Frans G
FG
Leufkens
Hubert G M
HG
D018806:APACHE; D000328:Adult; D000368:Aged; D001509:Bed Occupancy / Q000706:statistics & numerical data; D001569:Benzodiazepines / Q000627:therapeutic use; D015986:Confounding Factors, Epidemiologic; D017723:Drug Utilization Review / Q000706:statistics & numerical data*; D005260:Female; D006785:Hospitals, University; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D007902:Length of Stay / Q000706:statistics & numerical data; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D017891:Pharmacoepidemiology; D011619:Psychotropic Drugs / Q000145:classification / Q000627:therapeutic use*; D012189:Retrospective Studies
D011619:Psychotropic Drugs; D001569:Benzodiazepines