Differentiation between pain-related interference and interference caused by the functional impairments of spinal cord injury

Association of sensory phenotype with quality of life, functionality, and emotional well-being in patients suffering from neuropathic pain

ABSTRACT

Neuropathic pain highly affects quality of life, well-being, and function. It has recently been shown based on cluster analysis studies that most patients with neuropathic pain may be categorized into 1 of 3 sensory phenotypes: sensory loss, mechanical hyperalgesia, and thermal hyperalgesia. If these phenotypes reflect underlying pathophysiological mechanisms, they may be more relevant for patient management than underlying neurological diagnosis or pain intensity. The aim of this study was thus to examine the impact of these sensory phenotypes on mental health, functionality, and quality of life. Data of 433 patients from the IMI/EuroPain network database were analyzed, and results of HADS-D/A, Pain Catastrophizing Scale, Euro Quality of Life 5D/-VAS, Brief Pain Inventory, and Graded Chronic Pain Scale between the sensory phenotypes were compared using multiple regression analysis. There was no difference in chronic pain grade, pain intensity, depression, or anxiety scores between phenotypes. Pain interference (Brief Pain Inventory) was higher (P = 0.002); self-reported health state lower (Euro Quality of Life 5D VAS, P = 0.02); and problems regarding mobility (P = 0.008), usual activities (P = 0.004), and self-care (P = 0.039) more prominent (EQ5-D) in the sensory loss compared with the thermal hyperalgesia phenotype. Patients with sensory loss also showed higher pain catastrophizing scores (P = 0.006 and 0.022, respectively) compared with the 2 other groups. Sensory phenotype is associated with the impact of neuropathic pain conditions on well-being, daily functionality, and quality of life but is less associated with pain intensity. These results suggest that the somatosensory phenotype should be considered for personalized pain management.

The reliability of end of day and ecological momentary assessments of pain and pain interference in individuals with spinal cord injury

PURPOSE

This study investigated the most efficient means of measuring pain intensity and pain interference comparing ecological momentary assessment (EMA) to end of day (EOD) data, with the highest level of measurement reliability as examined in individuals with spinal cord injury.

METHODS

EMA (five times throughout the day) and EOD ratings of pain and pain interference were collected over a 7-day period. Multilevel models were used to examine the reliability for both EOD and EMA assessments in order to determine the amount of variability in these assessments over the course of a week or the day, and a multilevel version of the Spearman-Brown Prophecy formula was used to estimate values for reliability.

RESULTS

Findings indicate the minimum of number of EOD and EMA assessments needed to achieve different levels of reliability ("adequate" > 0.70, "good" > 0.80 and excellent > 0.90). In addition, the time of day (either morning, midday or evening) did not impact the estimated reliability for the EMA assessments.

CONCLUSIONS

These findings can help researchers and clinician balance the cost/benefit tradeoffs of these different types of assessments by providing specific cutoffs for the numbers of each type of assessment that are needed to achieve excellent reliability.

Quality of life after spinal cord injury: The impact of pain

BACKGROUND

Pain is a common complication after spinal cord injury (SCI). A mixture of nociceptive and neuropathic pain (NP) can present. Limited studies have investigated the impact of different pain phenotypes on quality of life (QoL) post-SCI.

METHODS

Members registered to a national support group for those with SCIs were surveyed (n = 1574). The survey comprised questions relating to demographics and SCI characteristics, The Douleur Neuropathique 4 (DN4) (interview), the International SCI Pain Basic Data Set recording the worst pain and the World Health Organisation Quality of Life BREF (WHOQOL-BREF). An ANCOVA model with post hoc analysis explored between group factors of pain type and intensity of pain categories on QoL, controlling for additional confounding variables. Significance was set p < 0.05. A linear regression explored whether pain intensity, type or interference best predicted QoL.

RESULTS

The response rate was 41% (n = 643), 70% (n = 447) were male. The mean age of respondents was 52 years (SD 14.2) and mean time from SCI was 17 years (SD 12.4). In the previous week, 71% (n = 458) experienced pain, 37% (n = 236) of which had NP as defined in the study. Respondents experiencing NP demonstrated significantly poorer QoL than those without pain (p < 0.001) or nociceptive pain (p < 0.05). Those reporting high pain intensity had significantly lower QoL than those with moderate or no pain (p < 0.001). Pain interference consistently and best-predicted domains of QoL (p < 0.001).

CONCLUSION

High-intensity pain and NP negatively impacts QoL post-SCI. However pain interference more than intensity or type best explains the variance in QoL reported.

SIGNIFICANCE

Neuropathic pain type and severe pain intensities negatively impact QoL after SCI. Pain interference items better predict reported QoL than either pain type or intensity, suggesting better pain management strategies are warranted.

Measuring pain phenomena after spinal cord injury: Development and psychometric properties of the SCI-QOL Pain Interference and Pain Behavior assessment tools

OBJECTIVE

To develop modern patient-reported outcome measures that assess pain interference and pain behavior after spinal cord injury (SCI).

DESIGN

Grounded-theory based qualitative item development; large-scale item calibration field-testing; confirmatory factor analyses; graded response model item response theory analyses; statistical linking techniques to transform scores to the Patient Reported Outcome Measurement Information System (PROMIS) metric.

SETTING

Five SCI Model Systems centers and one Department of Veterans Affairs medical center in the United States.

PARTICIPANTS

Adults with traumatic SCI.

INTERVENTIONS

N/A.

OUTCOME MEASURES

Spinal Cord Injury - Quality of Life (SCI-QOL) Pain Interference item bank, SCI-QOL Pain Interference short form, and SCI-QOL Pain Behavior scale.

RESULTS

Seven hundred fifty-seven individuals with traumatic SCI completed 58 items addressing various aspects of pain. Items were then separated by whether they assessed pain interference or pain behavior, and poorly functioning items were removed. Confirmatory factor analyses confirmed that each set of items was unidimensional, and item response theory analyses were used to estimate slopes and thresholds for the items. Ultimately, 7 items (4 from PROMIS) comprised the Pain Behavior scale and 25 items (18 from PROMIS) comprised the Pain Interference item bank. Ten of these 25 items were selected to form the Pain Interference short form.

CONCLUSIONS

The SCI-QOL Pain Interference item bank and the SCI-QOL Pain Behavior scale demonstrated robust psychometric properties. The Pain Interference item bank is available as a computer adaptive test or short form for research and clinical applications, and scores are transformed to the PROMIS metric.

Prevalence and factors associated with a higher risk of neck and back pain among permanent wheelchair users: a cross-sectional study

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

To determine the prevalence of, and factors associated with, spinal pain among wheelchair users.

SETTING

Four Spanish hospitals specialized in providing care for wheelchair users.

METHODS

Persons who had used a wheelchair for a median (IRQ) of 10 (5;19) years, 27% of them due to reasons other than spinal cord injury, were recruited consecutively (n = 750). Data on 43 demographic, psychosocial, ergonomic, and clinical variables were collected, and analyzed. Main outcome measures were: point prevalence of neck (NP), thoracic (TP), low back pain (LBP), and pain at any spinal level (PASL); and factors associated with them.

RESULTS

Point prevalence was 56% for NP, 54% for TP, 45% for LBP, and 76% for PSAL. PASL was associated with a lower quality of life (OR (95% CI) 0.91 (0.86; 0.97)). Multivariable regression models showed that the main factors associated with significant pain (≥1.5 VAS points) were: (a) For NP: cervical spinal injury and wheelchair seat cushion thickness, (b) For TP: thoracic spinal injury and sagittal index, (c) For LBP: thoracic or lumbar spinal injury, with some sensitivity remaining, (d) For PASL: being female, living alone, and using a non-power wheelchair. Discrimination (AUC) of these models ranged between 0.638 and 0.818. p-values in the Hosmer-Lemeshow test ranged between 0.420 and 0.701.

CONCLUSIONS

Prevalence of spinal pain among wheelchair users is high. It is associated with a lower quality of life. Future studies should assess whether using a power wheelchair affects PASL, and if the thickness of seat cushion affects NP.

SPONSORSHIP

Spanish Back Pain Research Network.

Psychometric evaluation of the Spanish version of the MPI-SCI

STUDY DESIGN

Postal surveys.

OBJECTIVES

To confirm the factor structure of the Spanish version of the MPI-SCI (MPI-SCI-S, Multidimensional Pain Inventory in the SCI population) and to test its internal consistency and construct validity in a Spanish population.

SETTING

Guttmann Institute, Barcelona, Spain.

METHODS

The MPI-SCI-S along with Spanish measures of pain intensity (Numerical Rating Scale), pain interference (Brief Pain Inventory), functional independence (Functional Independence Measure), depression (Beck Depression Inventory), locus of control (Multidimensional health Locus of Control), support (Functional Social Support Questionnaire (Duke-UNC)), psychological well-being (Psychological Global Well-Being Index) and demographic/injury characteristics were assessed in persons with spinal cord injury (SCI) and chronic pain (n=126).

RESULTS

Confirmatory factor analysis suggested an adequate factor structure for the MPI-SCI-S. The internal consistency of the MPI-SCI-S subscales ranged from acceptable (r=0.66, Life Control) to excellent (r=0.94, Life Interference). All MPI-SCI-S subscales showed adequate construct validity, with the exception of the Negative and Solicitous Responses subscales.

CONCLUSIONS

The Spanish version of the MPI-SCI is adequate for evaluating chronic pain impact following SCI in a Spanish-speaking population. Future studies should include additional measures of pain-related support in the Spanish-speaking SCI population.

Mismatch Between Investigator-Determined and Patient-Reported Independence After Spinal Cord Injury

Objective. This study investigated the course and relationship between investigator-determined and patient-reported level of independence within the first year after spinal cord injury (SCI). The authors examined variables that contributed to these scores. Methods. In this observational cohort study, 73 patients with traumatic SCI were evaluated at 1, 3, and 6 months (and 40 subjects at 1 to 12 months). The investigator-determined independence was quantified using the Spinal Cord Independence Measure (SCIM). The subjective, patient-reported independence was determined by asking how their general restrictions influenced everyday life activities. Several variables were used to explain these 2 scores. Results. The SCIM score was higher than the patient-reported independence and improved significantly more over time (up to about 70/100 at 12 months), whereas the perceived independence remained below 50/100. The correlations between the 2 measures were at most moderate ( rs ≤ 0.51), but in general somewhat higher for subjects with tetraplegia. Age and muscle strength predicted the SCIM score well. No variable predicted the patient-reported level of independence. Conclusions. Investigator-determined and patient-reported outcomes can differ considerably and evolve differently. A patient-reported outcome measure may not detect actual functional improvement. It is likely that changes in patient-reported outcomes are influenced by many factors in addition to those associated with functional recovery, including psychological factors.

Pain symptom profiles in persons with spinal cord injury

OBJECTIVE

Persistent pain is a common consequence of spinal cord injury. A patient-specific assessment that combines both the identification of pain symptoms and psychosocial factors is needed for a tailored treatment approach. The aim of the study was to define pain symptom profiles and to determine their relationship with psychosocial factors in persons with spinal cord injury.

DESIGN

Face-to-face interview and examination.

SETTING

VA Medical Center and Miami Project to Cure Paralysis, Miami, Florida.

PATIENTS

Persons with spinal cord injury (135 men and 21 women) provided detailed descriptions of 330 neuropathic pains.

OUTCOME MEASURES

The American Spinal Injury Impairment Scale, pain history and measures of pain interference, life satisfaction, locus of control, social support and depression.

RESULTS

The exploratory factor analyses and regression analyses revealed three distinct symptom profiles: 1) aching, throbbing pain, aggravated by cold weather and constipation predicted by a combination of chance locus of control and lower levels of life satisfaction; 2) stabbing, penetrating, and constant pain of high intensity predicted by a combination of pain interference, localized pain, powerful others locus of control and depressed mood; and 3) burning, electric, and stinging pain aggravated by touch and muscle spasms predicted by pain interference.

CONCLUSIONS

Although these results need to be replicated in other spinal cord injury samples, our findings suggest that pain symptom profiles may be a useful way to further characterize pain in a comprehensive assessment strategy.