Postoperative opioid consumption and its relationship to cognitive function in older adults with hip fracture

Abstract

Objectives: To determine the relationship between opioid consumption and cognitive impairment after hip fracture repair.

Design: Prospective study of consecutive patients.

Setting: Johns Hopkins Bayview Medical Center, Baltimore, Maryland.

Participants: Two hundred thirty-six participants aged 65 and older undergoing hip fracture repair.

Measurements: Older adults without preoperative delirium who underwent hip fracture repair between April 2005 and July 2009 were followed for pain, opioid consumption, and postoperative delirium. Participants were tested for delirium using the Confusion Assessment Method preoperatively and midmorning on Postoperative Day 2. The nursing staff assessed pain on a numeric oral scale (range 0-10). Opioid analgesia was provided in response to pain at rest to achieve scores of 3 or less. Opioid consumption was analyzed with respect to the occurrence of incident postoperative delirium, presence of dementia, and other demographic variables.

Results: Of the 236 participants, 66 (28%) had dementia, and 213 (90%) received opioids postoperatively, including 55 (83%) with dementia and 158 (93%) without. There was no association between the use of any postoperative opioid and incident delirium (P = .61) in participants with (P = .33) and without (P = .40) dementia. Dementia, but not postoperative delirium, was associated with less opioid use (P < .001 for dementia; P = .12 for delirium; P = .04, for their interaction; Wald chi-square = 142.8, df = 7). Opioid dose (P ≥ .59) on Postoperative Days 1 and 2 was not predictive of incident delirium. Dementia (P < .001) and intensive care unit admission (P = .006), not opioid consumption, were the most important predictors of incident postoperative delirium.

Conclusion: Concern for postoperative delirium should not prevent the use of opioid analgesic therapy sufficient to achieve a generally accepted level of comfort in individuals with or without preexisting cognitive impairment.

Figure 1

Postoperative opioid consumption in hip fracture patients receiving any postoperative opioid. Panel A: Postoperative opioid consumption in hip fracture patients with and without probable dementia (mean ± SEM). Panel B: Postoperative opioid consumption as a function of probable dementia, postoperative delirium, neither, or both (mean ± SEM). In the total patient population, postoperative delirium was not associated with alterations in opioid consumption. As revealed by longitudinal analysis, probable dementia, but not postoperative delirium, was associated with significantly less opioid use (P<0.001 for dementia; P=0.120 for delirium; P=0.038, for their interaction; Wald χ² =142.8 with 7 d.o.f.). Furthermore, opioid dose (P≥0.591) on postoperative days 1 and 2 was not predictive of incident delirium. All opioids were converted to their analgesic equivalent of intravenous (i.v.) morphine sulfate as described in the text.

Figure 1

Postoperative opioid consumption in hip fracture patients receiving any postoperative opioid. Panel A: Postoperative opioid consumption in hip fracture patients with and without probable dementia (mean ± SEM). Panel B: Postoperative opioid consumption as a function of probable dementia, postoperative delirium, neither, or both (mean ± SEM). In the total patient population, postoperative delirium was not associated with alterations in opioid consumption. As revealed by longitudinal analysis, probable dementia, but not postoperative delirium, was associated with significantly less opioid use (P<0.001 for dementia; P=0.120 for delirium; P=0.038, for their interaction; Wald χ² =142.8 with 7 d.o.f.). Furthermore, opioid dose (P≥0.591) on postoperative days 1 and 2 was not predictive of incident delirium. All opioids were converted to their analgesic equivalent of intravenous (i.v.) morphine sulfate as described in the text.