Table 1 Studies examining the association between pain and delirium
From: Pain and delirium: mechanisms, assessment, and management
Paper | Population | Key findings |
|---|---|---|
Post-operative populations | ||
Vaurio et al. [9] | 333 patients ≥ 65 years scheduled for major non-cardiac surgery. Mean age 74 ± 6 years | 46% developed post-operative delirium. Multivariable logistic regression: Moderate pain on VAS increases CAM delirium OR 2.19 (1.2–4.01). Severe pain increases delirium OR 3.72 (1.54–8.96) |
Kosar et al. [10] | 459 patients ≥ 70 years scheduled for elective orthopaedic surgery. Median age 76 (73–80) | 23% developed post-operative CAM delirium. Preoperative pain (BPI) increased adjusted risk of delirium (RR 1.6 (1.2–2.3) per one-pot increase in pain) |
Denny et al. [11] | 49 patients ≥ 65 following elective joint replacement surgery. Mean age 74 ± 6 years | 69% had post-operative sub-syndromal delirium (SSD). SSD severity increased by approximately 0.5 points (MDAS), with each point increase of pain on the NPRS (β = .53, t (42) = 2.141, p < .05, 95% CI [0.030, 1.032]) |
Morrison et al. [12] | 541 patients with hip fracture and without preoperative delirium. Age < 70 = 9%, 70–79 = 26%, 80 + 65% | Severe pain significantly increased delirium risk (CAM) (RR 9.0, 95% CI 1.8–45.2) |
Lynch et al. [13] | 86 patients > 50 years admitted for major elective noncardiac surgery | Higher pain scores at rest were positively associated with an increased risk of delirium over the 3 days immediately following surgery (arr 1.20, p = 0.04) |
Acute hospital medical inpatients | ||
Feast et al. [14] | 229 patients ≥ 75 years with dementia and medical illness. Age 75–84 = 37%, 85–94 = 51%, 95 +=27% | 11% delirious at baseline. Pain at rest increased delirium risk OR 3.26 (1.03–10.25) |
Goebel et al. [15] | 68 older adults with delirium aged > 65 | 39 patients screened positive for pain using PAINAD (57.3%). PAINAD reliability was strong (Chronbach’s α = 0.81–0.87) |
Care homes | ||
Kolanowski et al. [4] | 103 skilled nursing facility residents, mean age 86 ± 6.8 years | Delirium symptoms (CAM) were present on 64% of person-days. On days, where residents experienced increased pain, they had more delirium symptoms (p < 0.001) |