6 PHARMACOECONOMICS

'Unsatisfactory' outcomes increase cost of antihypertensive therapy

Drug acquisition costs rise with an increase in the number of modifications to antihypertensive therapy, according to US study data.

Retrospective analysis of pharmacy claims data from 6 managed-care organisations showed that during the first 12 months, therapy was modified at least once for 41 % of 936 patients receiving an ACE inhibitor and 46% of 996 patients receiving a calcium antagonist.

The most frequent initial modification for the respective treatment groups was an increase in dosage (40%) and the addition of a new class of drug (25%). The most frequent second modification was a switch in drug class for both groups (37 and 28%, respectively).

Acquisition costs Cost data showed that first-year drug acquisition

costs were $US322 and $US427 per patient receiving unmodified treatment with an ACE inhibitor or calcium antagonist, respectively. The increase in acquisition costs relative to the number of modifications to therapy is detailed in the table.

The study authors note that these data suggest that increasing the dosage or introducing combination therapy more quickly are 'logical first steps and have an acceptable rate of subsequent modification '.

Antihypertensive costs relative to the number of modifications to therapy

Number of Mean first-year acquisition costs' modifications (SUS/patient)

ACE Inhibitors Calcium antagonists

1 390 496

2 4n 537

3 007 649

4 555 708

5 fIJ9 629

6 880 861

• Costs were defined as the average wholesale price disoounted by 10"10

Wilson M. Patwell J. Shoheiber O. Brixner D. Kalmanowicz J. et al. The

clinical and economic implications of drug utilization patterns in the treatment

of hypertension with ACE inhibitors and calcium channel blockers in a managed care setting. Journal of Managed Care Pharmacy 4: 194-202. Mar-Apr 1998

Inpharma" 2 May 1998 No. 1135 1173·8324/98/1135·0006/$01.00'" Adis International Limited 1998. All rights reserved