Early discontinuation: more frequent among general practitioners with high levels of prescribing.
BACKGROUND
Discontinuation of medical drug treatment is a serious problem in primary care. The need for a better understanding of the processes, including physician-specific mechanisms, is apparent. The aim of this study was to analyse the association between general practitioners' prescribing prevalence and rate of early discontinuation of different drugs consisting of, in this study, lipid-lowering drugs, antihypertensive drugs, antidepressants, antidiabetics and drugs against osteoporosis.


METHODS
This was a register study based on prescription data covering a 4-year period and consisting of 470,000 citizens. For each practice and group of drug, a 1-year prevalence for 2002 and the rate of early discontinuation among new users in 2002-2003 were estimated. Early discontinuation was defined as no prescriptions during the second half-year following the first prescription, with the exception of new users of antidepressants for whom it was the first half-year. Correlations were analysed using the SAS ver. 9.1PROC MIXED procedure. The association with the total prescribing prevalence (all drugs) was also analysed.


RESULTS
A total of 141 general practices were included in the study. There was a positive association between the prevalence of prescribing for the specific drugs studied (antidepressants, antidiabetics, drugs against osteoporosis and lipid-lowering drugs) and early discontinuation (r = 0.29 -0.44), but not for anti-hypertensive drugs. The analysis of the association between prevalence of all drugs and drug-specific early discontinuation showed some degree of positive association - strongest for anti-hypertensive drugs (r = 0.62) and antidepressants (r = 0.43).


CONCLUSIONS
This study confirmed our hypothesis that general practitioners with high levels of prescribing attain higher rates of early discontinuation compared with colleagues with low levels of prescribing, not only with respect to antidepressants but also for various groups of drugs. A common underlying mechanism is suggested but has to be verified in future studies.
Hansen
Dorte Gilså
DG
Research Unit of General Practice, University of Southern Denmark, J.B. Winsløws Vej 9, 5000, Odense, Denmark. dgilsaa@health.sdu.dk
Gichangi
Anthony
A
Vach
Werner
W
Felde
Lina Hoel
LH
Larsen
John
J
D000928:Antidepressive Agents / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000627:therapeutic use; D016208:Databases, Factual / Q000706:statistics & numerical data; D003718:Denmark; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D004363:Drug Utilization / Q000706:statistics & numerical data; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D010024:Osteoporosis / Q000188:drug therapy / Q000517:prevention & control; D010361:Patients / Q000706:statistics & numerical data; D010601:Pharmacology, Clinical / Q000379:methods / Q000706:statistics & numerical data; D010821:Physicians, Family / Q000592:standards / Q000706:statistics & numerical data; D010818:Practice Patterns, Physicians' / Q000592:standards / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D013997:Time Factors; D028761:Withholding Treatment / Q000706:statistics & numerical data* / Q000639:trends
D000928:Antidepressive Agents; D000959:Antihypertensive Agents; D007004:Hypoglycemic Agents