Cost evaluation of therapeutic drug monitoring of gentamicin at a teaching hospital in Malaysia
Background: Therapeutic drug monitoring (TDM) makes use of serum drug concentrations as an adjunct to decision-making. Preliminary data in our hospital showed that approximately one-fifth of all drugs monitored by TDM service were gentamicin.
Objective: In this study, we evaluated the costs associated with providing the service in patients with bronchopneumonia and treated with gentamicin.
Methods: We retrospectively collected data from medical records of patients admitted to the Hospital Universiti Sains Malaysia over a 5-year period. These patients were diagnosed with bronchopneumonia and were on gentamicin as part of their treatment. Five hospitalisation costs were calculated; (i) cost of laboratory and clinical investigations, (ii) cost associated with each gentamicin dose, (iii) fixed and operating costs of TDM service, (iv) cost of providing medical care, and (v) cost of hospital stay during gentamicin treatment.
Results: There were 1920 patients admitted with bronchopneumonia of which 67 (3.5%) had TDM service for gentamicin. Seventy-three percent (49/67) patients were eligible for final analysis. The duration of gentamicin therapy ranged from 3 to 15 days. The cost of providing one gentamicin assay was MYR25, and the average cost of TDM service for each patient was MYR104. The average total hospitalisation cost during gentamicin treatment for each patient was MYR442 (1EUR approx. MYR4.02).
Conclusion: Based on the hospital perspective, in patients with bronchopneumonia and treated with gentamicin, the provision of TDM service contributes to less than 25% of the total cost of hospitalization.
2. Gogtay NJ, Kshirsagar NA, Dalvi SS. Therapeutic drug monitoring in a developing country: an overview. Br J Clin Pharmacol. 2001;52(Suppl 1):103S-108S.
3. Setiabudy R. Therapeutic drug monitoring: focus on conditions in Indonesia. Acta Med Indones. 2011;43(3):208-211.
4. Schumacher GE, Barr JT. Economic and outcome issues for therapeutic drug monitoring in medicine. Ther Drug Monit. 1998;20(5):539-542.
5. Destache CJ. Use of therapeutic drug monitoring in pharmacoeconomics. Ther Drug Monit. 1993;15(6):608-610.
6. Touw DJ, Neef C, Thomson AH, Vinks AA; Cost-Effectiveness of Therapeutic Drug Monitoring Committee of the International Association for Therapeutic Drug Monitoring and Clinical Toxicology. Cost-effectiveness of therapeutic drug monitoring: a systematic review. Ther Drug Monit. 2005;27(1):10-17.
7. Ismail R, Sarriff A, Abdul Rahman AF. Therapeutic drug monitoring for gentamicin in Hospital Universiti Sains Malaysia. Med J Malaysia. 1990;45(1):57-64.
8. Ismail R, Haq AH, Azman M, Rahman AF. Therapeutic drug monitoring of gentamicin: a 6-year follow-up audit. J Clin Pharm Ther. 1997;22(1):21-25.
9. Saunders NJ, Adams DJ, Lynn WA. A prospective laboratory-based audit of gentamicin use and therapeutic monitoring. J Antimicrob Chemother. 1995;36(4):729-736.
10. Rybak MJ, Abate BJ, Kang SL, Ruffing MJ, Lerner SA, Drusano GL. Prospective evaluation of the effect of an aminoglycoside dosing regimen on rates of observed nephrotoxicity and ototoxicity. Antimicrob Agents Chemother. 1999;43(7):1549-1555.
11. Ho KK, Thiessen JJ, Bryson SM, Greenberg ML, Einarson TR, Leson CL. Challenges in comparing treatment outcome from a prospective with that of a retrospective study: assessing the merit of gentamicin therapeutic drug monitoring in pediatric oncology. Ther Drug Monit. 1994;16(3):238-247.
12. Slaughter RL, Cappelletty DM. Economic impact of aminoglycoside toxicity and its prevention through therapeutic drug monitoring. Pharmacoeconomics. 1998; 14: 385-394.
13. Rougier F, Ducher M, Maurin M, Corvaisier S, Claude D, Jelliffe R, Maire P. Aminoglycoside dosages and nephrotoxicity: quantitative relationships. Clin Pharmacokinet. 2003;42(5):493-500.
14. Goldhaber-Fiebert JD, Denny LE, De Souza M, Wright TC, Kuhn L, Goldie SJ. The costs of reducing loss to follow-up in South African cervical cancer screening. Cost Eff Resour Alloc. 2005;3:11.
15. Ab Rahman AF, Abdelrahim HEA, Mohamad Ibrahim MI. A survey of therapeutic drug monitoring services in Malaysia. Saudi Pharm J. 2013;21(1):19-24. doi: 10.1016/j.jsps.2012.01.002
16. Gross AS. Best practice in therapeutic drug monitoring. Br J Clin Pharmacol. 2001;52(Suppl 1):5S-10S.
17. Hammett-Stabler CA, Johns T. Laboratory guidelines for monitoring of antimicrobial drugs. National Academy of Clinical Biochemistry. Clin Chem. 1998;44(5):1129-1140.
18. Begg EJ, Barclay ML, Kirkpatrick CM. The therapeutic monitoring of antimicrobial agents. Br J Clin Pharmacol. 2001;52(Suppl 1):35S-43S.
19. Martin JE. Commentary: once-daily aminoglycoside dosing: where are we now? J Crit Care. 2003;18(2):113-114.