Abstract
This research study compares the self-reported pain levels of geriatric vs nongeriatric patients with rib fractures.
Adequate pain control is the pillar of rib fracture management; patients must breathe comfortably to avoid pulmonary complications. Many rib fracture management decisions, such as escalating analgesic care, are grounded in improving patient-reported pain scores on the 10-point numerical rating scale (in which 0 indicates no pain and 10 the worst pain imaginable).1
Geriatric patients, who are known to have poorer outcomes after rib fractures compared with younger adults, have been shown to underreport pain.2,3,4 It is possible that geriatric patients with rib fractures underreport pain and may warrant a lower threshold to escalate analgesic care.
Methods
We retrospectively evaluated adult patients admitted for 4 or more days with isolated chest wall injuries at our level I trauma center between January 2012 to December 2017. The comparative groups were patients who were geriatric (≥65 years) vs nongeriatric (18-64 years). Stanford University’s institutional review board approved this study and waived informed consent requirement because this was a retrospective data review.
The primary outcome was numerical rating scale pain scores throughout the first 4 hospital days, in 12-hour increments. Fisher exact and Wilcoxon rank sum tests assessed group characteristic differences. Pain scores were compared using zero-inflated Poisson regression, which best models data with an excess of zeros.5 Zero-inflated Poisson regression provides the odds ratio for reporting no pain (in a zero-inflation model) and the mean ratio of pain scores for patients who report pain (in a count model). Confounders were included if they were both clinically relevant and changed the coefficient of the independent variable (geriatric status) by more than 10%. All analyses were conducted using R version 3.6.2 (R Foundation for Statistical Computing).6 Data analysis took place from June 2019 to December 2019. Any P value less than .05 was considered significant.
Results
Patient Characteristics
We identified 385 patients, of whom 166 were 65 years or older. Compared with the nongeriatric group, the geriatric group had more women (40 of 219 [18.3%] vs 88 of 166 [53.0%]; P < .001), different mechanisms of injury (eg, motorcycle crashes, 46 [21.0%] vs 4 [2.4%]; bicycle-associated injuries, 45 [20.5%] vs 13 [7.8%]; falls, 44 [20.0%] vs 100 [60.2%]; P < .001), and lower injury severity scores (median [IQR], 14 [4.0] vs 10.5 [4.0]; P < .001) (Table 1). Compared with the nongeriatric group, the geriatric group received fewer opioids per day (oral morphine equivalents: median [IQR], 177.1 [292.4] mg vs 75.5 [105.4] mg) and had similar rates of epidural use (29 [13.2%] vs 34 [20.5%]; P = .07) and nerve block use (11 [5.0%] vs 3 [1.8%]; P = .11).
Table 1. Baseline Characteristics of Adult Patients Admitted With Rib Fractures.
| Demographic characteristic | Age, No. (%) | P value | |
|---|---|---|---|
| <65 y (n = 219) | ≥65 y (n = 166) | ||
| Age, median (IQR), y | 52 (17.0) | 79.5 (15.0) | <.001 |
| Female | 40 (18.3) | 88 (53.0) | <.001 |
| Injury characteristics | |||
| Injury Severity Score, median (IQR) | 14 (4.0) | 10.5 (4.0) | <.001 |
| Sternal fracture | 17 (7.8) | 22 (13.3) | .09 |
| Clavicular fracture | 41 (18.7) | 15 (9.0) | .008 |
| Scapular fracture | 32 (14.6) | 14 (8.4) | .08 |
| No. of rib fractures, median (IQR) | 5.0 (3.0) | 5.0 (3.0) | .87 |
| Mechanism of injury | |||
| Motor vehicle crash | 59 (26.9) | 44 (26.5) | <.001 |
| Motorcycle crash | 46 (21.0) | 4 (2.41) | |
| Fall | 44 (20.0) | 100 (60.2) | |
| Bicycle-associated injury | 45 (20.5) | 13 (7.8) | |
| Other | 25 (11.4) | 5 (3.01) | |
| Hospitalization characteristics | |||
| Length of stay, median (IQR), d | 5.0 (4.5) | 5.0 (4.0) | .28 |
| Intensive care unit admission | 123 (56.2) | 136 (81.9) | <.001 |
| Disposition | |||
| Home | 153 (70.0) | 40 (24.1) | <.001 |
| Home health | 18 (8.2) | 25 (15.1) | |
| Skilled nursing facility | 18 (8.2) | 70 (42.2) | |
| Rehabilitation facility | 7 (3.2) | 2 (1.2) | |
| Other | 21 (9.6) | 22 (13.3) | |
| Deceased | 2 (0.9) | 7 (4.2) | .04 |
| Analgesic medication utilization | |||
| Oral morphine equivalents per day, median (IQR), mg | 177.1 (292.4) | 75.5 (105.4) | <.001 |
| Epidural | 29 (13.2) | 34 (20.5) | .07 |
| Time from admission to epidural administration, median (IQR), h | 17.0 (42.0) | 40.0 (38.3) | .18 |
| Nerve blocks | 11 (5.0) | 3 (1.8) | .11 |
Abbreviation: IQR, interquartile range.
Pain Scores
The adjusted odds ratio for reporting no pain was 3.85 (95% CI, 3.11-4.77) times higher in the geriatric group compared with the nongeriatric group (P < .001) (Table 2). Among patients who did report pain (pain score ≥1), pain scores were 15% lower in the geriatric group compared with the nongeriatric group (mean ratio, 0.85 [95% CI, 0.78-0.87]; P < .001). Subgroup analysis of patients with isolated rib fractures showed similar results (odds ratio for no pain, 5.08 [95% CI, 3.85-6.70]; P < .001; mean ratio of reported pain, 0.79 [95% CI, 0.74-0.84]; P < .001; Table 2).
Table 2. Zero-Inflated Poisson Regression Results.
| Injury to geriatric participants | Odds of having no paina | Comparative pain scores for patients who report painb | ||
|---|---|---|---|---|
| Odds ratio (95% CI) | P value | Mean ratio (95% CI) | P value | |
| Isolated chest wall injuries | ||||
| Unadjusted | 3.83 (3.19-4.60) | <.001 | 0.87 (0.83-0.91) | <.001 |
| Adjustedc | 3.85 (3.11-4.77) | <.001 | 0.85 (0.78. 0.87) | <.001 |
| Isolated rib fracturesd | ||||
| Unadjusted | 4.90 (3.90-6.16) | <.001 | 0.88 (0.84-0.93) | <.001 |
| Adjustede | 5.08 (3.85-6.70) | <.001 | 0.79 (0.74-0.84) | <.001 |
Zero-inflation model comparing the odds of having no pain, as indicated by a numerical rating scale pain score of 0.
Count model using comparative pain scores for patients who do report pain.
Adjusted for admission hour per 12-hour increments, sex, presence of sternal fracture, use of epidural analgesia, and use of nerve block analgesia.
Without scapular, clavicle, or sternal fractures.
Adjusted for admission hour per 12-hour increments, sex, use of epidural analgesia, and use of nerve block analgesia.
Discussion
Compared with nongeriatric patients, geriatric patients with rib fractures had higher odds of reporting no pain and, among those with pain scores, reported lower pain scores. However, we cannot differentiate whether geriatric patients underreported pain or truly experienced less pain.
Geriatric patients in this study had lower injury severity scores compared with nongeriatric patients; however, the difference was not clinically significant, and our regression model adjusted for injury severity. Despite similar overall injury patterns, geriatric patients had lower-force mechanisms of injury (eg, falls) and may have brittle bones that are easier to fracture compared with nongeriatric patients. Clinicians may have prescribed smaller amounts of opioids to geriatric patients because of judicious risk consideration. However, the proportion of patients receiving epidurals or nerve blocks were similar in both groups, and epidural analgesia was administered more promptly for nongeriatric patients.
Whether lower reported pain scores among geriatric patients reflect underreported pain or truly less pain remains unclear. In light of prior knowledge that geriatric patients underreport pain and patient-reported pain scores often dictate rib fracture analgesic management, it may be prudent to consider a lower pain score threshold for geriatric patients with rib fractures or place heavier weight on functional measures, such as incentive spirometry volumes, to escalate analgesic care.
Conclusions
The potential for geriatric patients with rib fractures to underreport pain requires recognition. More nuanced analgesic strategies for this high-risk group are needed.
References
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