The exploration of the establishment of cutpoints to categorize the severity of acute postoperative pain

OBJECTIVES: Although several studies have established different cutpoints (CPs) for mild, moderate, and severe pain for a variety of chronic pain conditions, only one study by Mendoza and colleagues reported on CPs for acute postoperative pain that were derived using ratings of worst pain. The purpose of this study was to explore the establishment of the optimal CPs for mild, moderate, and severe postoperative pain using ratings of average and worst pain and to determine if these CPs distinguished among the pain severity groups on several outcomes. METHODS: The study is a reanalysis of data from patients who underwent hip and knee replacement surgery. Using the methodology described by Serlin et al, a series of CP derivations were performed based on both single item scores for pain intensity and mean scores for pain intensity. One-way analyses of variance, chi analyses, or Kruskal-Wallis tests were conducted to determine if the optimal CPs for pain severity distinguished among the 3 pain severity groups on several outcomes. RESULTS: CPs 3,5 were found using a mean score based on patients' ratings of average and worst pain on the third postoperative day. Findings suggest that mean pain scores of >3 have a significant effect on general activity, mood, walking ability, and sleep. DISCUSSION: Possible explanations for the differences in the CPs found in this study compared with the results by Mendoza and colleagues are discussed. The findings warrant replication in other samples of postoperative patients.     

Mild,Moderate, and Severe Pain in Patients Recovering from Major Abdominal Surgery

Pain interferes with various activities, such as coughing, deep breathing, and ambulation, designed to promote recovery and prevent complications after surgery. Determining appropriate cutpoints for mild, moderate, and severe pain is important, because specific interventions may be based on this classification. The purpose of this research was to determine optimal cutpoints for postoperative patients based on their worst and average pain during hospitalization and after discharge to home, and whether the optimal cutpoints distinguished patients with mild, moderate, or severe pain regarding patient outcomes. This secondary analysis consisted of 192 postoperative patients aged ≥60 years. Multivariate analyses of variance were used to stratify the sample into mild, moderate, and severe pain groups using eight cutpoint models for worst and average pain in the last 24 hours. One-way analyses of variance were conducted to determine whether patients experiencing mild, moderate, or severe pain were different in outcome. Optimal cutpoints were similar to those previously reported, with the boundary between mild and moderate pain ranging from 3 to 4 and the boundary between moderate and severe pain ranging from 5 to 7. Worst pain cutpoints were most useful in distinguishing patients regarding fatigue, depression, pain's interference with function, and morphine equivalent administered in the previous 24 hours. A substantial proportion of patients experienced moderate to severe pain. The results suggest a narrow boundary between mild and severe pain that interferes with function. The findings indicate that clinicians should seek to aggressively manage postoperative pain ratings greater than 3.     

Cut points for mild,moderate, and severe pain on the VAS for children and adolescents: What can be learned from 10 million ANOVAs?

Cut points that classify pain intensity into mild, moderate, and severe levels are widely used in pain research and clinical practice. At present, there are no agreed-upon cut points for the visual analog scale (VAS) in pediatric samples. We applied a method based on Serlin and colleagues’ procedure (Serlin RC, Mendoza TR, Nakamura Y, Edwards KR, Cleeland CS. When is cancer pain mild, moderate or severe? Grading pain severity by its interference with function. PAIN® 1995;61:277–84) that was previously only used for the 0 to 10 numerical rating scale to empirically establish optimal cut points (OCs) for the VAS and used bootstrapping to estimate the variability of these thresholds. We analyzed data from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) study and defined OCs both for parental ratings of their children’s pain and adolescents’ self-ratings of pain intensity. Data from 2276 children (3 to 10 years; 54% female) and 2982 adolescents (11 to 17 years; 61% female) were analyzed. OCs were determined in a by-millimeter analysis that tested all possible 4851 OC combinations, and a truncated analysis were OCs were spaced 5 mm apart, resulting in 171 OC combinations. The OC method identified 2 different OCs for parental ratings and self-report, both in the by-millimeter and truncated analyses. When we estimated the variability of the by-millimeter analysis, we found that the specific OCs were only found in 11% of the samples. The truncated analysis revealed, however, that cut points of 35:60 are identified as optimal in both samples and are a viable alternative to separate cut points. We found a set of cut points that can be used both parental ratings of their children’s pain and self-reports for adolescents. Adopting these cut points greatly enhances the comparability of trials. We call for more systematic assessment of diagnostic procedures in pain research.     

Asking the community about cutpoints used to describe mild, moderate, and severe pain.

Clinical practice guidelines recommend that numeric rating scales be used to document the severity of perceived pain, yet patients and clinicians often opt to use simpler classification systems such as mild, moderate, or severe. To assess how well the numeric scales correlate with the tri-level classification system for describing pain severity, we conducted a subanalysis of a larger population-based study of pain management preferences. Our primary objective was to identify the numeric boundaries used by 287 adults to describe pain as mild, moderate, or severe. We examined differences in the means of the upper and lower limits for mild, moderate, and severe pain according to demographic characteristics and type of pain. Ranges reported for each pain level were 1.3 to 3.6 (mild), 4.3 to 6.5 (moderate), and 7.5 to 9.8 (severe). The primary finding was that "healthy" community adults rated the pain severity cutpoints much as patients with clinical pain did, 1 to 4 for mild, 5 to 6 for moderate, and 7 to 10 for severe. These results suggest that numeric rating scales can be used in clinical practice with both patients and community-dwelling adults. Our findings also support encouraging the general public to use a 0 to 10 scale to rate their pain intensity. PERSPECTIVE: Methods used to describe numeric cutpoints for mild, moderate, and severe pain were applied to community adults. Having standard categories to describe pain severity might increase clinicians' confidence in using a numeric scale to make treatment decisions. Further studies of cutpoint methodology and its clinical importance are warranted.     

Validation of brief pain inventory to Brazilian patients with pain

Purpose  

To validate the Brazilian version of the Brief Pain Inventory (BPI-B) scale and to determine the optimal cutpoints for mild, moderate, and severe pain based on patients' rating of their worst pain.     

Hazards for pain severity and pain interference with daily living, with exploration of brief pain inventory cutpoints, among women with metastatic breast cancer

Few longitudinal studies have assessed risk factors for pain outcomes in tumor-specific populations. Such studies are needed to improve clinical practice guidelines for cancer pain management over the course of treatment. Among patients with metastatic breast cancer, we assessed the impact of baseline clinical and demographic risk factors on patients reaching different pain severity and interference scores. We analyzed data originally collected in a clinical trial of two bisphosphonate therapies. Pain was measured by the Brief Pain Inventory (BPI) severity and interference with daily living 0-10 subscales. We fit univariate (per-cutpoint) and multivariate (cutpoints 3, 4, 5, 6, and 7 on the BPI) proportional hazards models to identify predictors of pain outcomes over 51 weeks among 1,124 women with metastatic breast cancer. Predictors included race, age, education, geographic region, performance status, chemotherapy versus hormonal therapy only, time from first bone metastasis to randomization, and previous skeletal-related event (SRE, e.g., fractures, spinal cord compression). Non-Caucasian women had greater hazards for reaching higher cutpoints (5 and above) on the severity scale than Caucasian women (hazard ratio [HR] for cutpoint 5 interaction term=1.76; 95% confidence interval [CI]=1.37-2.26). For the interference scale, these hazards were greater for those patients with restricted (versus active) baseline Eastern Cooperative Oncology Group (ECOG) performance status (HR for cutpoint 5 interaction term=2.51; 95% CI=2.01-3.13). In the multivariate severity model, other factors associated with higher pain severity were restricted baseline ECOG performance status, previous SRE, and not being employed full-time at baseline (HRs=1.70, 1.23, and 1.33, respectively). Our findings that non-Caucasian race and restricted performance status were associated with greater pain hazards over time confirm previous cross-sectional findings that these characteristics are pain risk factors. Because we found that the most influential demographic and clinical baseline factors had predictive value for worsening outcomes as early as cutpoint 5, we recommend that pain management strategies use cutpoints informed by risk factors for worsening outcomes as cues for earlier intervention, thus delaying or preventing worst pain among women with metastatic disease who are at greatest risk.     

Development of a metric for a day of manageable pain control: derivation of pain severity cut-points for low back pain and osteoarthritis

The objective of this study was to adapt the concept of 'episode-free day', a metric for measuring symptom relief in daily units, to the clinical outcome literature for persistent pain. The episode-free day metric is widely used in other medical literature, but no analogous measure exists in pain literature. Prior focus groups with this population suggested that a 'Day of Manageable Pain Control' was an appropriate name for the metric. In the present study, in order to derive a statistical criterion for 'Manageable Day', we used Serlin et al.'s (Pain 61 (1995) 277) cut-point derivation method to derive a single cut-point on a 0-10 scale of average pain that divided groups with significant persistent pain optimally on pain-related functional interference. Participants were 194 patients with moderate-severe low back pain (n=96) or osteoarthritis (n=98). For both patient samples, '5' was the cut-point that optimally distinguished groups on pain-related interference. '5-8' and '5-7' were double cut-point solutions that optimally divided LBP and OA samples into three categories (e.g. lowest, medium and highest average pain), respectively. Derived cut-points were confirmed using a variety of measures of functional disability. Together with research that showed that average pain ratings of approximately 5 and below permit increased function and quality of life in patients with moderate to severe low back pain and osteoarthritis, our findings provide support for the use of 0-5 on a 0-10 numeric average pain severity scale as one possible criterion for a Manageable Day.     

Pain site and the effects of amputation pain: further clarification of the meaning of mild, moderate, and severe pain

Research among persons with cancer pain suggests that the association between pain intensity and pain interference is non-linear. That is, pain begins to have a serious impact on functioning when it reaches a certain threshold level (about 5 on 0--10 scales). Often, a second pain threshold can be identified which, once reached, shows an even greater proportional negative impact on functioning. This finding supports the potential clinical utility of classifying pain as mild, moderate, and severe based on the impact of pain on quality of life, and research among persons with cancer pain supports specific cutoffs (mild: 1--4, moderate: 5--6, severe: 7--10, see Pain 61 (1995) 277) for this classification. The current study sought to replicate the non-linear association between pain and pain interference in a non-cancer pain sample, determine whether the cutoffs that have been identified as optimal for cancer patients are also optimal for persons with pain associated with amputation, and determine whether the optimal cutoffs replicate across pain types (in this case, phantom limb, back, and general pain) within a single sample. Two-hundred and five persons with acquired amputation and phantom limb pain, back pain, or both, rated their average pain intensity and degree of pain interference for each type of pain. The results support a non-linear association between pain intensity and pain interference. However, the optimal cutoffs for classifying mild, moderate and severe pain in the present sample replicated the findings for persons with cancer pain only for back pain -- different optimal cutoffs were found for phantom limb and general pain. Moreover, the degree of pain interference appeared to vary as a function of pain type. The same level of back pain interfered more significantly with daily function than phantom limb pain did after pain levels reached five or more (on a 0--10 scale). These findings have implications for understanding the meaning of pain intensity levels, as well as for the assessment of pain intensity in persons with amputation-related pain.     

Pain interference in persons with spinal cord injury: classification of mild, moderate, and severe pain.

Pain intensity is commonly measured by patient ratings on numerical rating scales (NRS). However, grouping such ratings into categories may be useful for guiding treatment decisions or interpreting clinical trial outcomes. The purpose of this study was to examine pain intensity classification in 2 samples of persons with spinal cord injuries (SCI) and chronic pain. The first sample (n = 307) rated the average intensity and activity interference of pain in general, and the second sample (n = 174) rated their worst pain problem. Pain intensity was categorized as mild, moderate, or severe using 4 possible classification systems; analyses were performed to determine the classification system that best distinguished the pain intensity groups in terms of activity interference. In both samples, the optimal mild/moderate boundary was lower (mild = 1-3 on a 0-10 NRS scale) than that reported previously for individuals with other pain problems. The possibility that pain may interfere with activity at lower levels for individuals with SCI requires further exploration. The moderate/severe boundary suggested by previous research was confirmed in only one of the samples. Implications for the assessment of pain intensity and functioning in persons with SCI and pain are discussed. PERSPECTIVE: Although pain in individuals with SCI is common, more research is needed regarding its characteristics and treatment. This study sought to develop an empirically based classification system for mild, moderate, and severe pain that could be useful for applying clinical treatment guidelines and for interpreting the results of much-needed clinical trials.     

Lessons learned from a multiple-dose post-operative analgesic trial

Patients undergoing major surgery often require several days of post-operative analgesic management. However, little data are available on the course of post-operative pain during this period. Such data would be extremely helpful in planning treatment, formulating pain management guidelines, and determining how to construct multiple-dose post-operative analgesic clinical trials. The objectives of this study were to determine (1) if post-operative pain severity, as measured by a modified version of the Brief Pain Inventory (BPI), can be categorized as mild, moderate, or severe in terms of modified BPI pain interference scores, (2) the relationship between modified BPI pain ratings and responses to a categorical item that specifically measures post-sternotomy pain, and (3) the relationship between global ratings of study medication effectiveness and other pain measures. This study is a reanalysis of data from patients who underwent coronary artery bypass graft procedures. We found that the pain severity level cut points developed for chronic pain apply equally well to post-operative pain. Based on this classification scheme, 18% of patients reported moderate pain after day 3, while 14% reported severe pain. Only 9% of patients reported experiencing moderate-to-severe pain approximately 2 weeks later, at the end of the study. Describing pain as mild, moderate, or severe could be a simple, meaningful clinical trial outcome measure. Because most patients experience only mild pain 6 days after surgery, long-term clinical trials of post-operative pain control may be more efficient and cost-effective if they focus on the subset of patients with persistent moderate or severe pain.     

人膝骨关节炎滑膜血管活性肠肽的表达及其与疼痛的关系

目的:研究血管活性肠肽(vasoactive intestinal peptide,VIP)在人膝骨关节炎滑膜中的表达特点,并探讨其与患者膝关节疼痛程度之间的相关性。方法:采集18例骨关节炎患者膝关节滑膜,根据术前视觉模拟疼痛评分(visual analogue scale,VAS)分为轻中度疼痛组(M组)和重度疼痛组(S组),7例外伤病人滑膜作为对照组(C组)。检测患者和正常人滑膜内VIP的含量和位置。结果:正常膝关节和骨关节炎膝关节滑膜均表达VIP,滑膜衬里层和衬里下层的表达无显著性差异(P>0.05)。轻中度疼痛组(M组)滑膜VIP表达高于对照组(C组)和重度疼痛组(S组)(P<0.05)。VIP与疼痛无线性相关。结论:VIP可能在人膝骨关节炎中参与轻度致痛作用,而在重度疼痛中不起主要作用。     

Validation of the Brief Pain Inventory in a Taiwanese population

Assessment of pain in cancer patients is very important to all health care professionals. This paper describes the development of a Taiwanese version of the Brief Pain Inventory (BPI-T) and discusses its psychometric properties in Taiwan. The BPI-T was developed from the original BPI using back-translation and committee review. A total of 534 cytologically or pathologically diagnosed cancer patients in three medical centers in Taiwan were interviewed between July 1992 and October 1997. The intraclass correlation coefficient for the test-retest reliability was 0.79 for the pain severity scale and 0.81 for the pain interference scale. The explained variance for the within-scale factor analyses was larger than 60% in both scales. The coefficient alpha for the internal reliability was 0.81 for the severity scale and 0.89 for the interference scale. Confirmatory factor analysis of the BPI-T clearly identified the same two scales (severity and interference scales) in the 299 adult patients (age between 20-64) with high education (education years > 9) or patients at an early stage of disease. However, in the 235 nonadult patients with distant metastasis or low education patients with distant metastasis, the "most severe pain" item loaded more to the interference scale than the severity scale. Convergent validity of the pain severity was demonstrated by significant correlations with stage of disease (National Cancer Institute's Surveillance, Epidemiology, and End Results Program [SEER]), performance status (Eastern Cooperative Oncology Group [ECOG]), and pain interference. In conclusion, interviewer-administered BPI-T was a reliable instrument for cancer pain severity and its interference in Taiwan. Additionally, it was a valid instrument on adult cancer patients with high education or patients at an early stage of disease.     

Persistent Breast Pain Following Breast Cancer Surgery Is Associated With Persistent Sensory Changes,Pain Interference,and Functional Impairments

Interindividual variability exists in persistent breast pain following breast cancer surgery. Recently, we used growth mixture modeling to identify 3 subgroups of women (N = 398) with distinct persistent breast pain trajectories (ie, mild, moderate, severe) over 6 months following surgery. The purposes of this study were to identify demographic and clinical characteristics that differed among the breast pain classes and, using linear mixed effects modeling, to examine how changes over time and in sensitivity in the breast scar area, pain qualities, pain interference, and hand and arm function differed among these classes. Several demographic and clinical characteristics differentiated the breast pain classes. Of note, 60 to 80% of breast scar sites tested were much less sensitive than the unaffected breast. Significant group effects were observed for pain qualities and interference scores, such that, on average, women in the severe pain class reported higher scores than women in the moderate pain class. In addition, women in the moderate pain class reported higher scores than women in the mild pain class. Compared to women in the mild pain class, women in the severe pain class had significantly impaired grip strength, and women in the moderate and severe pain classes had impaired flexion and abduction.PerspectiveSubgroups of women with persistent postsurgical breast pain differed primarily with respect to the severity rather than the nature or underlying mechanisms of breast pain. Pervasive sensory loss and the association between persistent breast pain and sustained interference with function suggest the need for long-term clinical follow-up.     

Refractory chronic migraine: long-term follow-up using a refractory rating scale

Refractory chronic migraine (RCM) is often associated with disability and a low quality of life (QOL). RCM ranges in severity from mild to severe. There would be a benefit both clinically and in research use in categorizing RCM patients according to severity. This study utilized a unique RCM severity rating scale, tracking the clinical course over 10 years. A total of 129 patients, ages 19–72, were assigned a severity rating of 2–10 (10 = worst). Pain level and QOL were assessed. Over the 10 years, 73% of all pts. had a 30% or more decline in pain. Pain levels improved 45% in mild pts., 42% in mod. pts., and 36% in severe pts. Pain was the same, or worse, in 4% of mild, 15% of mod., and 18% of severe pts. QOL in the mild group improved 35% over 10 years. In moderate pts., QOL improved 32%, while for the severe group QOL improved 33%. While pain and QOL improved across all three groups at the end of 10 years, the severe group remained with significantly more pain and decreased QOL than in the milder groups. The medications that helped significantly included: opioids (63% of pts. utilized opioids), frequent triptans (31%), butalbital (17%), onabotulinumtoxinA (16%), stimulants (12%), and other “various preventives” (9%). RCM pts. were rated using a refractory rating scale with the clinical course assessed over 10 years. Pain and QOL improved in all groups. In the severe group, pain and QOL improved, but still lagged behind the mild and moderate groups. Opioids and (frequent) triptans were the most commonly utilized meds.     

Establishing mild, moderate, and severe scores for cancer-related symptoms: how consistent and clinically meaningful are interference-based severity cut-points?

Methods are presented to separate 16 frequently occurring cancer symptoms measured on 10-point symptom severity rating scales into mild, moderate, and severe categories that are clinically interpretable and significant for use in oncology practice settings. At their initial intervention contact, 588 solid tumor cancer patients undergoing chemotherapy reported severity on a standard 11-point rating scale for 16 symptoms. All reporting a one or higher were asked to rate on an 11-point scale how much the symptom interfered with enjoyment of life, relationship with others, general daily activities, and emotions. Factor analysis revealed that these items tapped into the same dimension, and the items were summed to form an interference scale. Cut-points for mild, moderate, and severe categories of symptom severity were defined by comparing the differences in interference scores corresponding to each successive increases in severity for each symptom. The cut-points differed among symptoms. Pain, fatigue, weakness, cough, difficulty remembering, and depression had lower cut-points for each category compared to other symptoms. Cut-points for each symptom were not related to site or stage of cancer, age, or gender but were associated with a global depression measure. Cut-points were related to limitations in physical function, suggesting differences in the quality of patients' lives. The resulting cut-points summarize severity ratings into clinically significant and useful categories that clinicians can use to assess symptoms in their practices.     

Validation of the Brief Pain Inventory for chronic nonmalignant pain.

The Brief Pain Inventory (BPI; Cleeland and associates) has been used primarily to assess patients with cancer-related pain. Although it has been validated in many languages and is widely used, there has not yet been research published to validate its use for patients with chronic nonmalignant pain as the primary presenting problem. This study was designed to fill this gap by examining the psychometric properties of the BPI in 440 patients with chronic intractable pain referred to a chronic pain clinic at a metropolitan tertiary-care teaching hospital. Results indicated acceptable internal consistency (Cronbach alpha coefficients were.85 for the intensity items and.88 for the interference items). A factor analysis resulted in 2 distinct and independent factors, supporting the validity of the 2-factor structure of the BPI. Zero-order correlations indicated that the association with a measure of disability (the Roland-Morris Disability Questionnaire [RMDQ]) was significantly higher for BPI interference (r = 0.57) than for BPI intensity (r = 0.40, t = 5.71, P <.01) and that the correlation with BPI interference was not more than 0.80, supporting the conclusion that these scales assess related, but also distinct, dimensions. Finally, the finding that both BPI scales showed statistically significant improvement with treatment confirms the responsivity of BPI in detecting and reflecting improvement in pain over time. PERSPECTIVE: This paper validated the psychometric properties of a pain Assessment instrument (The Brief Pain Inventory) originally developed to assess cancer pain and extended its use for the chronic nonmalignant pain population. This provides an important and widely used diagnostic tool for the clinician treating chronic pain.