Abstract
Objective
To examine the most common patterns of pain and symptom management strategies among adults living with cerebral palsy (CP), and to determine if there are differences by pain phenotype or co-occurring neurodevelopmental disorders.
Patients and Methods
Federally insured beneficiaries were included if they had an ICD-9-CM/ICD-10-CM diagnosis code for CP (N=41,595). The study took place from January 10, 2024, to December 15, 2024. Medication and therapy prescription estimates for pain and CP symptom management were examined for the entire cohort, and between individuals with and without neurodevelopmental disorders and across pain phenotypes.
Results
The most common pharmaceutical/nontherapy-based pain and symptom management interventions included high frequency prescriptions for antiepileptics (58%), antidepressants (49%), benzodiazepines (43%), nonsteroidal anti-inflammatories (43%), nonperioperative opioids (42%), antipsychotics (33%), muscle relaxants (31%), irritable bowel syndrome-specific drugs (20%), clonidine (12%), anticholinergics (11%), and botulinum toxin A injections (6%). Physical and occupational therapy were prescribed for 41% of the study cohort. Significant differences in treatment patterns were found for individuals with co-occurring neurodevelopmental disorders, and across pain phenotypes. Notably, for individuals with a mixed pain phenotype, nearly 80% were prescribed nonperioperative opioids.
Conclusion
Adults with CP have a high prescription prevalence of nonperioperative opioids and common nonopioid pain and symptom management.
Cerebral Palsy (CP) is the most common lifelong physical disability,1 with an estimated prevalence ranging from 2.6-3.1 cases per 1000 live births in the United States.2,3 Pain is a very prevalent somatic symptom among individuals with CP, with up to 90% of adults having a diagnosis related to pain at some point, and over 70% experiencing pain multimorbidity.4 Pain interferes with overall function, and participation and quality of life. Despite this, chronic pain is perhaps the least understood, emphasized, and studied comorbidity of CP,5, 6, 7 and pain management has largely been confined to peripherally-directed interventions.
Pain in CP is due to multiple etiologies, such as nociceptive mechanisms associated with chronic muscle spasticity, joint misalignment, and invasive and repetitive surgical procedures.8 Neuropathic mechanisms may be peripheral, such as neuralgia from nerve entrapments related to contractures,9 or from skeletal abnormalities such as spondylosis causing radiculopathy.10 They may also be central due to periventricular leukomalacia, which causes dysfunction of nonnociceptive sensory tract neurons in most people with CP.8 New evidence has reported all pain subtypes, such as nociplastic pain, are present in the CP population, with many patients experiencing a combination of pain subtypes.4 In particular, patients with CP have many risk factors that can contribute to the development of nociplastic pain, including a history of chronic nociceptive or neuropathic pain. In spite of the evidence suggesting an important role for nociplastic pain in adults with CP, a recent review concluded that the prevalence of nociplastic pain in children with CP has not been studied at all.4,11,12 Understanding the phenotypes of chronic pain among patients with CP is crucial for prescribing the most appropriate and effective pain management interventions-matching treatments to underlying pain mechanisms.
Pain management in CP is complex, as many treatments interact with other common sequelae of CP such as abnormal muscle tone, movement disorders, cognitive deficits, psychiatric disorders, and seizure disorders. Communication deficits, difficulties with executive function, and certain social determinants of health, such as limits on access to transportation and health insurance, all represent additional barriers to compliance with typical treatment.13 These factors may lead to wide variability across clinical providers for pain treatment decision-making for patients with CP. The objective of this study was to determine the use of pharmacologic treatments and physical/occupational therapy for adults with CP, examining patterns across different phenotypic presentations and differences on the basis of the presence of epilepsy or additional intellectual or developmental disorders.
Methods
Data Source
This is a retrospective cohort study of adults with CP whose diagnosis could have existed across any patient care setting. The study took place from January 10, 2024, to December 15, 2024. We used Medicare Fee-for-Service research identifiable files from the 20% random sample from 2008 to 2020. Medicare is federal health insurance for anyone aged ≥65 years and some people <65 years with certain disabilities or conditions. Medicaid is a joint federal and state program that gives health coverage to some people with limited income and resources.14 These data include the master beneficiary summary file (MBSF), Medicare provider analysis and review, outpatient file, carrier file for office visit identification, and part D drug event file. Medicare claims captured by these files were used for cohort identification and identifying service utilization. Enrollment information from the MBSF includes person-month indicators for Medicare managed care and dual eligibility (Medicare and Medicaid) critical for this study. The MBSF also includes sociodemographic information This study was deemed not regulated by the University of Michigan institutional review board and included a Waiver of HIPAA consent as required by The Centers for Medicare & Medicaid Services for use of the data. Although the data contain identifiable information, they do not contain direct identifiers necessary for obtaining consent.
Sample Selection
Individuals ≥18 years at the beginning of 2016 were potentially eligible for the study. We identified individuals with CP from International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and/or International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnosis codes on a claim across any patient setting captured in the research identifiable files from 2008 to 2020. The primary study period for pain and treatment observation was from 2016 to 2020; however, because CP is a congenital disability that could be diagnosed and detected at any time during the patient’s enrollment in Medicare, we searched all claims from 2008 to 2020 to identify eligible patients. We excluded individuals who were not continuously enrolled in Medicare fee-for-service (both parts A and B) and Medicare part D exclusively from 2016 to 2020 for at least 12 continuous months.
We restricted to patients with part D coverage to consistently capture information about pharmaceutical treatment for pain. Although we used claims from 2008 to 2020 to identify CP diagnoses, all information regarding pain diagnoses and treatments was drawn from 2016 to 2020. This was done to avoid complications in comparing pain and treatment rates between the ICD9 and ICD10 eras. With respect to Medicaid and Medicare dual eligibility and potential for differences in prescribing and treatment utilization for patients with CP from their nondual eligible counterparts, we did not perform any exclusions on the basis of a patient’s eligibility for any type of Medicaid during this time. To enable flexible evaluation, we flagged patients with CP on the basis of their dual eligibility status code with designations for 02, 04, and 08 for full eligibility and 01, 03, 05, and 06 for partial eligibility for Medicaid on the basis of previous guidance for each individual patient-month of enrollment. We also considered beneficiaries who had only a portion of their enrollment covered dually to be partially dually eligible. Only patients who were located in the 48 contiguous United States, Alaska, Hawaii, and District of Columbia were included.
Pain Phenotypes
We identified pain diagnoses on the basis of ICD-10-CM diagnosis codes from claims in any patient setting from 2016 to 2020 informed by previous expert guidance and literature.15 We flagged the existence of each of these 3 pain phenotypes (nociceptive, nociplastic, and neuropathic) across the study period for each patient. Mixed pain phenotypes were defined as the existence of 2 or more separate specific categories for a given patient. The complete list of codes used to identify phenotypes has been previously established.4
Neurodevelopmental disorders
Presence of co-occurring neurodevelopmental disorders (NDDs) were based on ICD-10-CM diagnosis codes from claims in any patient setting from 2016 to 2020 for intellectual disabilities, autism spectrum disorder, and epilepsy (Supplemental Appendix, available online at http://www.mcpiqojournal.org).
Pain and Symptom Management
National drug codes were used to identify outpatient pharmacy claims in consultation with clinical and technical experts as common approaches to manage pain and CP symptom management. Specific drug classes examined were (1) nonperioperative opioids, (2) antiepileptics, (3) antidepressants, (4) benzodiazepines, (5) nonsteroidal anti-inflammatories, (6) antipsychotics, (7) muscle relaxants, (8) irritable bowel syndrome-specific drugs, (9) clonidine, (10) anticholinergics, (11) botulinum toxin A injections, (12) antihistamines, (13) CNS stimulants, (14) metoclopramide, (15) migraine medication, and (16) Parkinson tremor medication. For opioids, we removed prescriptions filled within 30 days after a surgery and reported both evidence of any opioid prescription and a standardized dose by creating daily oral morphine equivalents (OME). The identification of the perioperative period was based on evidence of current procedural terminology codes for various procedures for anesthesia that would typically be applied during surgical operations and consistent with previously published work.16, 17, 18 The current procedural terminology codes were also used to determine evidence of any physical and/or occupational therapy (PT/OT) and botulinum toxin A injection prescription in the enrollment period using the professional and outpatient claims informed by previous literature.19 Furthermore, to better understand use patterns of these drugs, we used part D drug event data to identify periods in which each patient was continuously prescribed an opioid. Any lapse between prescription periods of 14 days or fewer was counted as continuous coverage for this purpose. We used these prescription periods to calculate the average OME per day that a patient was receiving while prescribed opioids.
Statistical Analyses
Counts and proportions of demographic characteristic information were calculated for the entire cohort, along with prevalences by specific pain phenotypes. To better understand the treatment patterns for pain and symptom management in the population, we found each medication class and evidence of PT/OT and botulinum toxin A injections with counts greater than 100 within the cohort. We also compared the counts and proportions of each treatment outcome among individuals with versus without co-occurring NDDs and across different pain phenotypes. All analyses were conducted using SAS Software, Version 9.4 (SAS Institute).
Results
After exclusions, we identified 41,595 eligible adults with CP that met the inclusion criteria. The mean age of our cohort was 48.9 years old (standard deviation [SD]: 15 years). Approximately 27% of the cohort was non-White and 22,451 (54.0%) individuals were male. Nearly 91% of our population was dually eligible for some form of Medicaid for some of the study period, whereas 72% were fully eligible and enrolled in Medicaid across the entire study period. Among the entire cohort, 24,707 (59.4%) had co-occurring intellectual impairments. All demographic characteristics are included in Table 1.
Table 1.
Descriptive Characteristics of Adults With CP With and Without Co-Occurring NDDs
| Characteristic | Total |
Without NDDs |
With NDDs |
|---|---|---|---|
| (N=41,595) | (n=16,888) | (n=24,707) | |
| Age (y) | |||
| Mean ± SD | 48.9±14.95 | 48.7±15.77 | 49.1±14.36 |
| Median | 50 | 49 | 50 |
| Range | 18.0-104.0 | 18.0-104.0 | 19.0-95.0 |
| Sex, n (%) | |||
| Male | 22,451 (54.0%) | 9028 (53.5%) | 13,423 (54.3%) |
| Female | 19,144 (46.0%) | 7860 (46.5%) | 11,284 (45.7%) |
| Race, n (%) | |||
| White | 30,495 (73.3%) | 12,109 (71.7%) | 18,386 (74.4%) |
| Black | 6148 (14.8%) | 2654 (15.7%) | 3494 (14.1%) |
| Asian | 602 (1.4%) | 277 (1.6%) | 325 (1.3%) |
| Hispanic | 3337 (8.0%) | 1305 (7.7%) | 2032 (8.2%) |
| Other/unknown | 1013 (2.4%) | 543 (3.2%) | 470 (1.9%) |
| Dual enrollment, n (%) | |||
| None | 3836 (9.2%) | 2907 (17.2%) | 929 (3.8%) |
| Partial | 7825 (18.8%) | 4309 (25.5%) | 3516 (14.2%) |
| Full | 29,934 (72.0%) | 9672 (57.3%) | 20,262 (82.0%) |
| Enrollment (mo) | |||
| Mean ± SD | 49.1±15.83 | 46.1±17.00 | 51.1±14.63 |
| Median | 60 | 59 | 60 |
| Range | 12.0-60.0 | 12.0-60.0 | 12.0-60.0 |
| Pain yes/no, n (%) | |||
| No | 5529 (13.3%) | 2476 (14.7%) | 3053 (12.4%) |
| Yes | 36,066 (86.7%) | 14,412 (85.3%) | 21,654 (87.6%) |
| Pain phenotypes, n (%) | |||
| Nociceptive pain only | 15,973 (38.4%) | 5001 (29.6%) | 10,972 (44.4%) |
| Nociceptive + nociplastic pain | 11,887 (28.6%) | 4567 (27.0%) | 7320 (29.6%) |
| Neuropathic + nociceptive + nociplastic pain | 5229 (12.6%) | 3337 (19.8%) | 1892 (7.7%) |
| Neuropathic + nociceptive pain | 1856 (4.5%) | 988 (5.9%) | 868 (3.5%) |
| Nociplastic pain only | 1121 (2.7%) | 519 (3.1%) | 602 (2.4%) |
| None | 5529 (13.3%) | 2476 (14.7%) | 3053 (12.4%) |
Pain Phenotypes
There were 36,066 (86.7%) adults with CP with evidence of one or more documented pain diagnoses. Notably, only 17,094 (41.1%) had a single pain phenotype throughout the study period, whereas 18,972 (45.6%) exhibited a mixed pain phenotype. The most common phenotypes were evidence of nociceptive pain only (38.4%), followed by nociceptive + nociplastic pain (28.6%), neuropathic + nociceptive + nociplastic pain (12.6%), and neuropathic + nociceptive pain (4.5%) (Table 1) (all P<.001).
Pain and Symptom Management by Pain Phenotype
Table 2 provides a complete breakdown of the pain and symptom management approaches by these 4 common phenotype combinations, and for individuals with no pain diagnosis(es). In general, mixed pain phenotypes were associated with increased prescription of medication and therapy services. For example, patients with a mixed pain phenotype consisting of all 3 subtypes of pain (nociceptive + neuropathic + nociplastic) had a high use rate of nonperioperative opioids (79.8%), followed by neuropathic + nociceptive (56.4%), and nociceptive + nociplastic (50.9%). By comparison, only 32.2% patients with nociceptive pain only, 27% with nociplastic pain only, and 15.8% with no pain had evidence of nonperioperative opioid prescriptions.
Table 2.
Pain Treatment and Symptom Management by Common Pain Phenotypes
| No Pain |
Neuropathic Pain/Nociceptive Pain |
Neuropathic Pain/Nociceptive Pain/Nociplastic Pain |
Nociceptive Pain |
Nociceptive Pain/Nociplastic Pain |
|
|---|---|---|---|---|---|
| (n=5529, 13.3%) | (n=1856, 4.5%) | (n=5229, 12.6%) | (n=15,973, 38.4%) | (n=11,887, 28.6%) | |
| Botulinum toxin A injections, n (%) | 41 (0.7%) | 153 (8.2%) | 661 (12.6%) | 958 (6.0%) | 912 (7.7%) |
| Nonperioperative opioids, n (%) | 872 (15.8%) | 1046 (56.4%) | 4175 (79.8%) | 5149 (32.2%) | 6054 (50.9%) |
| PT/OT, n (%) | 423 (7.7%) | 1086 (58.5%) | 3517 (67.3%) | 6180 (38.7%) | 5871 (49.4%) |
| Antidepressants, n (%) | 1630 (29.5%) | 1051 (56.6%) | 3940 (75.3%) | 6302 (39.5%) | 6786 (57.1%) |
| Antiepileptics, n (%) | 2395 (43.3%) | 1245 (67.1%) | 4172 (79.8%) | 8857 (55.4%) | 7010 (59.0%) |
| Anticholinergics, n (%) | 411 (7.4%) | 190 (10.2%) | 508 (9.7%) | 1876 (11.7%) | 1506 (12.7%) |
| Antihistamines, n (%) | 55 (1.0%) | 23 (1.2%) | 66 (1.3%) | 255 (1.6%) | 143 (1.2%) |
| Antipsychotics, n (%) | 1328 (24.0%) | 584 (31.5%) | 2209 (42.2%) | 4725 (29.6%) | 4675 (39.3%) |
| Benzodiazepines, n (%) | 1549 (28.0%) | 816 (44.0%) | 2896 (55.4%) | 6806 (42.6%) | 5387 (45.3%) |
| CNS stimulants, n (%) | 131 (2.4%) | 58 (3.1%) | 274 (5.2%) | 255 (1.6%) | 316 (2.7%) |
| Clonidine, n (%) | 301 (5.4%) | 329 (17.7%) | 1602 (30.6%) | 1339 (8.4%) | 1571 (13.2%) |
| IBS medications, n (%) | 372 (6.7%) | 407 (21.9%) | 2037 (39.0%) | 2320 (14.5%) | 3145 (26.5%) |
| Metoclopramide, n (%) | 95 (1.7%) | 112 (6.0%) | 486 (9.3%) | 948 (5.9%) | 856 (7.2%) |
| Migraine medications, n (%) | 19 (0.3%) | 24 (1.3%) | 483 (9.2%) | 68 (0.4%) | 517 (4.3%) |
| Muscle relaxants, n (%) | 557 (10.1%) | 790 (42.6%) | 3117 (59.6%) | 3873 (24.2%) | 4211 (35.4%) |
| NSAIDs, n (%) | 972 (17.6%) | 907 (48.9%) | 3647 (69.7%) | 5418 (33.9%) | 6422 (54.0%) |
| Parkinson tremors, n (%) | 47 (0.9%) | 106 (5.7%) | 501 (9.6%) | 374 (2.3%) | 468 (3.9%) |
Abbreviations: CMS, Centers for Medicare & Medicaid Services; CNS, central nervous system; IBS, irritable bowel syndrome; NSAID, nonsteroidal anti-inflammatory drug.
Nociplastic pain only not reported in compliance with CMS cell suppression policies.
Of the patients who were prescribed nonperioperative opioids, the median number of distinct enrollment prescriptions were 2 (IQR: 1-5) and median days prescribed were 11.5 days (IQR: 4.8-57d). Furthermore, patients with documented pain symptoms received more opioid prescriptions (median 2 vs 1, P<.001), for longer periods of time (median 12.8d vs 4d, P<.001). However, there was no differences in the strength of the dosage (mean 47.5 OMEs/d vs 43.6 OMEs/d P=.14) between patients with documented pain symptoms versus those without.
Nearly identical trends were observed for other drugs and botulinum toxin A injections, with mixed pain phenotypes being prescribed significantly more frequently than for individuals with single phenotypes or for individuals with no pain. Outcomes were also similar for PT/OT, wherein between 49%-67% of the individual with mixed pain phenotypes had evidence of therapy prescriptions compared with only 38.7% for nociceptive pain only, 9.4% for nociplastic pain only, and 7.7% for no pain (Table 2).
Pain and Symptom Management by Co-Occurring NDDs
The average daily OMEs was 47.3±71.3. Patients with co-occurring NDDs were prescribed opioids less frequently (median 2 vs 3, P<.001), for shorter periods of time (median 8d vs 19.5d, P<.001), and at lower doses (mean 45.1 OMEs/d vs 49.4 OMEs/d, P<.001), compared with patients without co-occurring NDDs. Furthermore, patients who had CP with a co-occurring NDDs had significantly lower exposure to pain related medications and PT/OT when compared with those who had CP alone. For example, 52.3% of the CP alone group were exposed to nonperioperative opioids, whereas only 32.3% of the group with CP plus NDDs were prescribed opioids. Findings were similar for therapy, nonsteroidal anti-inflammatory drugs, muscle relaxants, and migraine medications. Conversely, individuals with co-occurring NDDs received significantly more antiepileptics, benzodiazepines, anticholinergics, antihistamines, and antipsychotics. Table 3 provides a breakdown of treatment prevalences for these 2 groups.
Table 3.
Pain Treatment and Symptom Management Stratified by Co-Occurring NDDs
| Total |
Without NDDs |
With NDDs |
|
|---|---|---|---|
| (N=41,595) | (n=16,888) | (n=24,707) | |
| Botulinum toxin A injections, n (%) | 2738 (6.6%) | 1495 (8.9%)∗ | 1243 (5.0%) |
| Nonperioperative opioids, n (%) | 16,952 (40.6%) | 8604 (50.7%)∗ | 8274 (33.4%) |
| PT/OT, n (%) | 17,182 (41.3%) | 7606 (45.0%)∗ | 9576 (38.8%) |
| Antidepressants, n (%) | 20,197 (48.6%) | 8284 (49.1%) | 11,913 (48.2%) |
| Antiepileptics, n (%) | 24,210 (58.2%) | 7875 (46.6%) | 16,335 (66.1%)∗ |
| Anticholinergics, n (%) | 4596 (11.0%) | 920 (5.4%) | 3676 (14.9%)∗ |
| Antihistamines, n (%) | 553 (1.3%) | 145 (0.9%) | 408 (1.7%)∗ |
| Antipsychotics, n (%) | 13,882 (33.4%) | 3731 (22.1%) | 10,151 (41.1%)∗ |
| Benzodiazepines, n (%) | 17,804 (42.8%) | 5634 (33.4%) | 12,170 (49.3%)∗ |
| CNS stimulants, n (%) | 1054 (2.5%) | 557 (3.3%)∗ | 497 (2.0%) |
| Clonidine, n (%) | 5227 (12.6%) | 2851 (16.9%)∗ | 2376 (9.6%) |
| IBS medications, n (%) | 8462 (20.3%) | 3672 (21.7%)∗ | 4790 (19.4%) |
| Metoclopramide, n (%) | 2548 (6.1%) | 778 (4.6%) | 1770 (7.2%)∗ |
| Migraine medications, n (%) | 1150 (2.8%) | 762 (4.5%)∗ | 388 (1.6%) |
| Muscle relaxants, n (%) | 12,733 (30.6%) | 6844 (40.5%)∗ | 5889 (23.8%) |
| NSAIDs, n (%) | 17,713 (42.6%) | 7952 (47.1%)∗ | 9761 (39.5%) |
| Parkinson tremors, n (%) | 1511 (3.6%) | 778 (4.6%)∗ | 733 (3.0%) |
Abbreviations: CNS, central nervous system; IBS, irritable bowel syndrome; NSAID, nonsteroidal anti-inflammatory drug.
P<.001.
Discussion
This is the first and largest study to examine pain and symptom treatment patterns on the basis of pain phenotypes and co-occurring NDDs among adults with CP. The nearly 87% pain prevalence revealed in this study again reports the importance of understanding and treating pain because it is likely that all adults with CP will have pain at some point in early to mid-adulthood. In addition, of the individuals with an existing pain diagnosis, over 50% exhibited a mixed pain phenotype. Mixed pain phenotypes increase the complexity of treatment decisions, and thus these findings highlight the necessity of understanding pain etiology to provide effective treatment options. These findings are also of critical importance for clinical and public health audiences, especially considering the high use of opioid medications in patients with pain multimorbidity.
The major contribution of this study is the reporting of pharmaceutical and therapy treatments that are associated with pain and symptom management in a large cohort of adults with CP. The findings here are an important first foray into examining these issues, and they will help develop pathways of research into pain treatment optimization in this population. For most medications, and in particular for those medications primarily prescribed for pain (opioids, nonsteroidal anti-inflammatory drugs, and muscle relaxants), individuals with mixed pain phenotype presentations had a considerably greater pattern of prescription, with the combination of all 3 pain subtypes generally at the highest level, ranging from 60% for muscle relaxants to 80% for the nonperioperative opioids. This may relate simply to having more pain diagnoses, or it may suggest that the interaction of different pain subtypes accentuates pain intensity and the need for treatment. For example, altered nociception is a feature of nociplastic pain, which may suggest that a mixed presentation including nociplastic pain will cause greater pain and require more intensive intervention. It is notable that nociplastic pain was common, found alone or in combination in greater than 40% of the cohort. As noted, nociplastic pain has not been well recognized in CP until recently,4,20,21 despite the many risk factors for it in patients with CP. A major risk factor for the development of nociplastic pain is the chronic presence of nociceptive pain. For example, patients with rheumatic diseases have a prevalence of fibromyalgia ranging from 10% to 48%.22,23 Other risk factors for nociplastic pain conditions include early life stressors, depression, anxiety, impaired sleep, obesity, and decreased physical activity,16,24 all of which are known to be highly prevalent among adults with CP.23,25,26 In addition, it is not known how early brain injury or malformation and early trauma from painful procedures common for premature babies (a major risk factor in CP) affect sensory pathways and put individuals at risk for nociplastic pain triggered by nociceptive or neuropathic injuries.
Opioid overuse is a major concern in adults with CP,22,25 and was found to be a commonly prescribed intervention among patients in this study. Of important concern is that mixed pain presentations, including nociplastic pain phenotypes had the highest prevalence of opioid treatment. It is well known that opioids are not an appropriate treatment for nociplastic pain and can actually worsen pain experience and exacerbate cognitive declines.23 Chronic overlapping pain, such as nociplastic pain benefits instead from a biopsychosocial approach involving nonpharmaceutical options, sleep hygiene, regular physical activity, and careful selection of centrally-acting medications.24 It is certainly possible that the increased prevalence of prescription opioids for adults with CP stems from the fact that they often have a mixed presentation with an easily identifiable target of pain (eg, joint arthritis), which could increase the willingness among clinicians to give opioids in spite of obvious signs and symptoms of nociplastic pain. Moreover, lack of clinical pain phenotyping knowledge/experience/expertise and individual barriers to accessing other nonpharmacologic modalities (eg mental health counseling, transportation, and caregiving assistance) likely also contribute to higher opiate prescribing patterns in this population.13
The different patterns of treatment prescription in adults with CP who do or do not have epilepsy or another NDD diagnosis may be in part because of their varying ability to interact with their caregivers, describe their pain and receive treatment. Many individuals with NDDs have communication difficulties and cannot present their pain or explain it with adequate detail. It is often difficult for the clinicians to identify and, in particular, localize pain with these patients.26 Many patients with co-occurring NDDs rely on caregivers to detect that they have pain and seek treatment for them, which can lead to inadequate recognition and diminished pain treatment effectiveness. Notably, this group had higher use of antiepileptics (as expected in a group identified for epilepsy), but also of antipsychotics and benzodiazepines. It is possible that these drugs were used for behavioral control rather than pain, as previously described.27 Moreover, the higher rate anticholinergics may have been related to control of drooling or bladder dysfunction. Polypharmacy is common in adults with CP, which further complicates pain identification and treatment, and could lead to cognitive/intellectual decline, increased risk of comorbidities, and under-prescription of appropriate pain treatment.28, 29, 30
There are several important limitations to be discussed. First, the study methodology did not allow for examining temporality and connections between treatments and pain. For medications prescribed for multiple reasons (eg, pain vs muscle relaxants), it was not determined if the treatment was specifically prescribed for the pain. Moreover, our methods did not allow for an accurate examination of the effects of polypharmacy, as medications could have been prescribed at different times during an individual’s enrollment period. We also do not have clear connections between treatment, pain presentations, and severity of the neurologic and function deficit related to the patients’ CP. This includes the inability to assess lifestyle and functional level information, such as the Gross Motor Function Classification System. Understanding the relationship between function and pain would contribute considerably to the overall understanding of pain in adults with CP and subsequent treatment efficacy. Finally, this study comes from administrative claims, which may contribute to a clinic bias (ie, people with pain seek out more medical services).
This study highlights several potential trends that should be examined and better understood, such as the effects of pain chronicity, presence of mixed pain phenotypes, and subsequent treatment patterns that may infer increased risk of addiction, mental health complications, respiratory issues, falls and fractures, and even preventable mortality. Future studies are needed to increase our understanding of the connection between comorbidities and the phenotypical presentation of pain in the context of optimal treatments for adults with CP. Moreover, studies are needed to address health disparities relating to intellectual disability, mental health disorders, and communication barriers pertaining to access to appropriate management of pain.
Conclusion
Adults with CP have a high prevalence of pain, and this often originates from a mixed pain phenotype. Patients with mixed presentations of pain phenotypes receive considerably more opioids, other pharmaceuticals, and therapy treatment than those with a single phenotype diagnosis or patients with no pain. The considerably high use of opioids suggests that nociplastic pain is not well recognized or correctly treated. Patients with CP with co-occurring NDDs receive less pain treatment than those without an NDD.
Potential Competing Interests
The authors report no competing interests.
Footnotes
Grant Support: This research was developed in part under a grant from the National Institutes of Health (grant no: #1R21DE032584-01).
Supplemental material can be found online at http://www.mcpiqojournal.org. Supplemental material attached to journal articles has not been edited, and the authors take responsibility for the accuracy of all data.
Supplemental Online Material
References
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