Pharmacist Performance of the DIE Test to Assess Aminoglycoside Vestibulotoxicity

ABSTRACT Background: Aminoglycoside antibiotics can cause irreversible vestibulotoxicity, leading to debilitating effects on balance and vision. The dynamic illegible E (DIE) test was developed at the authors’ institution to screen for signs of vestibulotoxicity and hence to prevent permanent vestibular damage; the test is currently conducted by a neurophysiologist. Objective: The primary goal of this study was to determine whether a pharmacist can perform the DIE test for vestibulotoxicity with accuracy equivalent to that of the neurophysiologist. The secondary goals were to determine the workload associated with conducting the DIE test and to correlate patient characteristics with occurrence of vestibulotoxicity. Methods: All patients starting aminoglycoside therapy over a 12-week period were screened. All patients older than 18 years of age and receiving a prescription for aminoglycoside therapy for more than 7 days were evaluated for suitability to undergo a DIE test. Patients were excluded if they were unable to sit up for the test, were unable to read at least the top 4 rows of the test chart (because of either visual impairment or mental incompetence), had a language barrier without a translator available, or had a medical contraindication to neck manipulation. Eligible patients were tested first by 1 of 2 pharmacists and were then retested, within 72 h, by the neurophysiologist. Results: A total of 213 patients were screened, of whom 38 were to receive aminoglycosides for more than 7 days. Fifteen of these patients were excluded because of a medical condition or discharge from the hospital before testing, and the remaining 23 were tested by a pharmacist. The neurophysiologist was unable to retest 7 of these patients, and 1 patient was tested twice; therefore, 16 patients and 17 DIE test results were included in the final analysis. The correlation between the results of the pharmacist and those of the neurophysiologist was 100%. There were no positive test results (score of 3 or more); therefore, no patients with vestibulotoxicity were identified. No aminoglycoside concentrations were considered supratherapeutic, and there were no changes in baseline patient characteristics such as serum creatinine or urea (as blood urea nitrogen). The DIE test took less than 3 min per patient. On average, only 2 or 3 patients would require this test each week, and hence the increase in pharmacist workload would be minimal. Conclusion: Pharmacists were able to perform the DIE test with equivalent accuracy to the control tester in patients who did not display vestibulotoxicity caused by aminoglycoside therapy. RESUME Historique : Les aminosides peuvent causer une vestibulotoxicite permanente, qui entraine des effets debilitants sur l’equilibre et la vision. Le test du «E illisible dynamique» (EID) a ete mis au point par l’etablissement auquel sont associes les auteurs, pour depister les signes de vestibulotoxicite et ainsi prevenir toute atteinte permanente du vestibule; ce test est actuellement administre par un neurophysiologiste. Objectif : Le principal objectif de cette etude etait de determiner si un pharmacien pouvait administrer le test EID et obtenir des resultats aussi precis que ceux du neurophysiologiste. Les objectifs secondaires etaient de determiner la charge de travail associee a l’administration de ce test et d’etablir une correlation entre les caracteristiques du patient et l’apparition de vestibulotoxicite. Methodes : Tous les patients qui amorcaient un traitement aux aminosides sur une periode de 12 semaines ont ete evalues. On a ensuite determine si les patients de plus de 18 ans qui recevaient une ordonnance pour un traitement de plus de sept jours aux aminosides etaient aptes a subir le test EID. Les patients etaient exclus s’ils etaient incapables de s’asseoir, de lire les quatre premieres lignes du tableau d’optotypes (a cause d’un trouble visuel ou d’incapacite mentale), de s’exprimer sans l’aide d’un interprete ou si une manipulation cervicale etait medicalement contre-indiquee. Le test a ete administre une premiere fois aux patients admissibles par l’un de deux pharmaciens, puis a nouveau 72 heures plus tard par le neurophysiologiste. Resultats : Au total, 213 patients ont ete evalues, dont 38 devaient recevoir un traitement de plus de sept jours aux aminosides. De ces 38 patients, 15 ont ete exclus a cause de leur etat de sante ou parce qu’ils avaient recu leur conge avant l’administration du test; les 23 autres ont ete examines par un pharmacien. Le neurophysiologiste n’a pu faire subir le test a 7 de ces 23 patients et a fait subir le test deux fois a un patient; c’est pourquoi l’analyse finale compte 16 patients et 17 resultats de test. On a pu etablir une correlation entre les resultats du pharmacien et ceux du neurophysiologiste dans 100 % des cas. Il n’y a eu aucun resultat positif au test (score de trois ou plus); par consequent, aucun patient n’etait atteint de vestibulotoxicite. Aucune concentration serique d’aminosides n’a ete consideree comme supratherapeutique et on n’a note aucune modification des parametres initiaux, comme la creatininemie ou l’azotemie. Il a fallu moins de trois minutes par patient pour administrer le test EID. En moyenne, il faudrait administrer ce test a seulement deux ou trois patients par semaine, pour une augmentation minime de la charge de travail du pharmacien. Conclusion : Les pharmaciens ont pu administrer le test EID de facon aussi precise que le controleur temoin chez les patients exempts de vestibulotoxicite consecutive au traitement aux aminosides.