PATIENT DEMOGRAPHICS AND HEALTH PLAN PAID COSTS IN CHRONIC INFLAMMATORY DEMYELINATING POLYNEUROPATHY JEFFREY T. GUPTILL, MD,1 MARK B. BROMBERG, MD, PhD,2 LI ZHU, PhD,3 BAL K. SHARMA, PhD,3 AMY R. THOMPSON, MBA,3 ANDREW KRUEGER, MD,3 and DONALD B. SANDERS, MD1 1
Department of Medicine - Neurology, Duke University Medical Center, DUMC Box 3403, Durham, North Carolina 27710 USA Department of Neurology, University of Utah, Salt Lake City, Utah USA 3 Accordant Health Services, A CVS Caremark Company, Greensboro, North Carolina USA Accepted 27 October 2013 2
ABSTRACT: Introduction: We determined health plan paid costs and healthcare resource usage of patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Methods: CIDP patients from 9 U.S. commercial health plans with claims in 2011 were identified from the Accordant Health Services claims database. We examined demographics, prevalence of comorbidities, prescribed drugs, place of service, and mean annual health plan paid costs per patient. Results: From 6.5 million covered lives, 73 (56% men; mean age 47) met study entry criteria. The most prescribed therapies were intravenous immunoglobulin (IVIg) (26% of patients), gabapentin (26%), and prednisone (16%). The annual health plan paid cost was $56,953. Pharmacy cost was the major cost driver (57% of the total), and IVIg totaled 90% of the pharmacy costs. Conclusions: Healthcare costs for CIDP patients are substantial, with a large burden in pharmacy usage. Studies are needed to determine optimal long-term treatment strategies for CIDP, particularly related to IVIg. Muscle Nerve 50: 47–51, 2014
Chronic
inflammatory demyelinating polyneuropathy (CIDP) is a debilitating disease characterized by distal and proximal limb weakness and sensory dysfunction affecting gait and activities of daily living. CIDP is a rare disease with an estimated prevalence of 1.0 to 8.9 per 100,000.1,2 Although the initiating event is unknown, an autoimmune response is directed against peripheral nerve myelin that may result in secondary axonal loss.3 CIDP is slowly progressive or relapsing and usually requires long-term treatment with immunosuppressive or immunomodulatory therapies to reduce morbidity and maintain function.4 We found no recent literature published from the United States that describes the burden of CIDP in terms of healthcare resource usage and costs. We performed a retrospective analysis of health insurance claims to describe patient demographics, determine healthcare costs, and identify Abbreviations: AHS, Accordant Health Services; AIDP, acute inflammatory demyelinating polyneuropathy; CI, confidence interval; CIDP, chronic inflammatory demyelinating polyneuropathy; EMG, electromyography; HCPCS, Healthcare Common Procedure Coding System; ICD-9, ninth revision of the International Classification of Diseases; IVIg, intravenous immunoglobulin; NDC, National Drug Code; PID, patient identification; POS, place of service; PPPY, per patient per year. Key words: chronic inflammatory polyradiculoneuropathy; CIDP; cost analysis; costs; health care cost; intravenous immune globulin Correspondence to: J.T. Guptill; e-mail: [email protected] C 2013 Wiley Periodicals, Inc. V
Published online 6 November 2013 in Wiley Online Library (wileyonlinelibrary. com). DOI 10.1002/mus.24109
Costs of CIDP
major cost drivers of healthcare for patients with CIDP. MATERIALS AND METHODS Data Source. The study included
all patients with a diagnosis of CIDP between January 1, 2011, and December 31, 2011 whose primary health plan was eligible for the Accordant Health Services (AHS) care management program.5 Patients must have had at least 1 health insurance claim during the study period. The patients’ member months during the analysis period were calculated from their health plan eligibility data. Data on patients from all types of health plans (e.g., Commercial, Medicare, and Medicaid) were included. Patient Identification and Demographics. Patients with CIDP were identified by the AHS patient identification (PID) algorithm,5 which uses the ninth revision of the International Classification of Diseases (ICD-9) diagnosis code 357.81, procedure codes, pharmacy usage, place of service (POS), and date of service. This algorithm was designed to increase the probability that patients included in the study truly had CIDP. The PID algorithm is an iterative decision-making process that reviews each study candidate’s healthcare usage over time using the criteria described above. Claims for patients who met some, but not all, of the criteria for CIDP by the PID algorithm were subjected to manual review. Reviewers did not have access to lumbar puncture results, clinic notes, or results of nerve conduction studies/electromyography (EMG) studies. Patients identified as having CIDP were excluded if they denied the CIDP diagnosis when contacted by AHS. To prevent exclusion of patients with CIDP who were initially coded as acute inflammatory demyelinating polyneuropathy (AIDP), ICD-9 codes for both CIDP and AIDP were included in the PID algorithm. However, the diagnosis of CIDP required at least 8 weeks of treatment after initial diagnosis. Patient age was calculated as of June 30, 2011. The age–gender distribution of the study population with CIDP was determined by deciles of age in years and was performed for the overall study population and by gender. The relative prevalence MUSCLE & NERVE
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47
of comorbidities was determined from examination of diagnosis codes in medical claims. Psychiatric diagnoses included multiple mental health-related conditions (e.g., affective psychosis, adjustment disorder, anxiety disorder, attention deficit disorder, bipolar disorder, depression). Because a patient could have multiple comorbidities, the total for different comorbidities could exceed 100%. Determining the Health Plan Paid Costs and Major Cost Drivers. The total health plan paid costs were summarized by patient. The resulting amount was divided by the number of total member months and multiplied by 12 to determine per patient per year (PPPY) costs. The mean health plan paid cost PPPY was analyzed further by claim category and comorbidity burden. Health plan paid costs were categorized as a pharmacy or medical cost; paid amounts not identified as a pharmacy cost were considered to be a medical cost. Pharmacy costs included the health plan paid costs for prescription drugs billed using National Drug Code (NDC) codes and the costs for injectable drug claims billed using Healthcare Common Procedure Coding System (HCPCS) codes from multiple POS settings (e.g., pharmacies, physician offices, home infusions, outpatient hospital settings). Pharmacy claims billed using NDC codes were used to identify the top drug classes and the most frequently prescribed drug names. The costs for intravenous immunoglobulin (IVIg) were identified as described previously.5 To determine the principal drivers of healthcare costs, a POS category was assigned as described in Guptill et al.,6 except that the costs for injectable drugs billed using HCPCS codes and those for the prescription drugs billed using NDC codes were determined separately. Statistical Analysis. This study used data for all CIDP patients who met the inclusion criteria, and no sampling was done. The cost data were not Winsorized (a statistical technique to limit extreme values), and outliers were not removed. The mean health plan paid cost PPPY is presented with its standard error of the mean, ranges, and 95% confidence intervals (CI). For descriptive purposes, the associations between variables were measured using the correlation procedure of SAS version 9.1 (SAS Institute, Cary, NC). RESULTS
Among 6.5 million covered lives in 9 health plans, 233 patients with an ICD-9 code for CIDP were identified. Using the AHS PID algorithm, this group was reduced to 73 patients who met study entry criteria for the cost analysis. Patients were excluded because their health plan
Demographics.
48
Costs of CIDP
FIGURE 1. Age distribution (deciles of years) by gender in 73 patients with chronic inflammatory demyelinating polyneuropathy. There is a bimodal distribution, with peaks for women in the third and sixth deciles. Peaks for men occur in the fourth and sixth deciles.
was not eligible for the AHS care management program (n 5 73), no eligible claims were filed during the study (n 5 8), or the patient denied the CIDP diagnosis (n 5 75). Patients who died (n 5 4) were also not included. Forty-four percent were women, and 56% were men. The mean age was 47 years, and the median age was 51 years. Five patients (3 women and 2 men) were younger than 19 years, and 3 (1 woman and woman men) were older than 65 years. There was a bimodal age distribution with peak distributions in the third and sixth deciles for women and in the fourth and sixth deciles for men (Fig. 1). The majority (93%) of patients were covered by a commercial health plan, and 7% were covered by Medicaid. These patients had a total of 574 clinic visits, and the mean number of visits per patient was 8.4 6 1 (median 5, range 1–41). Eight patients had paid claims for nerve conduction or EMG studies. Seven patients had both nerve conduction and EMG studies, and a total of 18 nerve conduction study and 7 EMG units were performed on those 8 patients. Forty percent of the CIDP patients had none of the 30 defined comorbidities, while 19% had 1, and 41% had 2 or more comorbidities. No patient had more than 7 comorbidities. The five most prevalent comorbidities were hypertension (29%), hyperlipidemia (27%), diabetes (16%), psychiatric diagnosis (15%), and hypothyroidism (12%) (Table 1). Among drugs billed using NDC codes, the five most common prescription drug classes were anticonvulsants (33%), analgesic opioids (27%), antihyperlipidemics (27%), antihypertensives (26%), and antidepressants (25%). Within these drug classes, the most commonly used drugs included MUSCLE & NERVE
July 2014
Table 1. Comorbidities with a relative frequency of 5% among 73 CIDP patients. Comorbidity* Hypertension Hyperlipidemia Diabetes Psychiatric diagnoses Hypothyroidism Anemia Asthma Cancer Osteoarthritis Coronary artery disease Headache
Percentage with comorbidity 29 27 16 15 12 8 7 7 7 5 5
*Other comorbidities examined were congestive heart failure, chronic obstructive pulmonary disease, dementia, dysphagia, epilepsy, gastroesophageal reflux disease, irritable bowel syndrome, infectious diarrhea, interstitial lung, lactose intolerance, migraine, pulmonary hypertension, obesity, osteoporosis, pulmonary fibrosis, renal failure, skin infection, sleep disorder, and urinary tract infection.
gabapentin (26%), prednisone (16%), azithromycin (14%), amoxicillin (10%), and lisinopril (10%) (Table 2). Steroid-sparing agents, including mycophenolate mofetil and azathioprine, were used in
Department of Medicine - Neurology, Duke University Medical Center, DUMC Box 3403, Durham, North Carolina 27710 USA Department of Neurology, University of Utah, Salt Lake City, Utah USA 3 Accordant Health Services, A CVS Caremark Company, Greensboro, North Carolina USA Accepted 27 October 2013 2
ABSTRACT: Introduction: We determined health plan paid costs and healthcare resource usage of patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Methods: CIDP patients from 9 U.S. commercial health plans with claims in 2011 were identified from the Accordant Health Services claims database. We examined demographics, prevalence of comorbidities, prescribed drugs, place of service, and mean annual health plan paid costs per patient. Results: From 6.5 million covered lives, 73 (56% men; mean age 47) met study entry criteria. The most prescribed therapies were intravenous immunoglobulin (IVIg) (26% of patients), gabapentin (26%), and prednisone (16%). The annual health plan paid cost was $56,953. Pharmacy cost was the major cost driver (57% of the total), and IVIg totaled 90% of the pharmacy costs. Conclusions: Healthcare costs for CIDP patients are substantial, with a large burden in pharmacy usage. Studies are needed to determine optimal long-term treatment strategies for CIDP, particularly related to IVIg. Muscle Nerve 50: 47–51, 2014
Chronic
inflammatory demyelinating polyneuropathy (CIDP) is a debilitating disease characterized by distal and proximal limb weakness and sensory dysfunction affecting gait and activities of daily living. CIDP is a rare disease with an estimated prevalence of 1.0 to 8.9 per 100,000.1,2 Although the initiating event is unknown, an autoimmune response is directed against peripheral nerve myelin that may result in secondary axonal loss.3 CIDP is slowly progressive or relapsing and usually requires long-term treatment with immunosuppressive or immunomodulatory therapies to reduce morbidity and maintain function.4 We found no recent literature published from the United States that describes the burden of CIDP in terms of healthcare resource usage and costs. We performed a retrospective analysis of health insurance claims to describe patient demographics, determine healthcare costs, and identify Abbreviations: AHS, Accordant Health Services; AIDP, acute inflammatory demyelinating polyneuropathy; CI, confidence interval; CIDP, chronic inflammatory demyelinating polyneuropathy; EMG, electromyography; HCPCS, Healthcare Common Procedure Coding System; ICD-9, ninth revision of the International Classification of Diseases; IVIg, intravenous immunoglobulin; NDC, National Drug Code; PID, patient identification; POS, place of service; PPPY, per patient per year. Key words: chronic inflammatory polyradiculoneuropathy; CIDP; cost analysis; costs; health care cost; intravenous immune globulin Correspondence to: J.T. Guptill; e-mail: [email protected] C 2013 Wiley Periodicals, Inc. V
Published online 6 November 2013 in Wiley Online Library (wileyonlinelibrary. com). DOI 10.1002/mus.24109
Costs of CIDP
major cost drivers of healthcare for patients with CIDP. MATERIALS AND METHODS Data Source. The study included
all patients with a diagnosis of CIDP between January 1, 2011, and December 31, 2011 whose primary health plan was eligible for the Accordant Health Services (AHS) care management program.5 Patients must have had at least 1 health insurance claim during the study period. The patients’ member months during the analysis period were calculated from their health plan eligibility data. Data on patients from all types of health plans (e.g., Commercial, Medicare, and Medicaid) were included. Patient Identification and Demographics. Patients with CIDP were identified by the AHS patient identification (PID) algorithm,5 which uses the ninth revision of the International Classification of Diseases (ICD-9) diagnosis code 357.81, procedure codes, pharmacy usage, place of service (POS), and date of service. This algorithm was designed to increase the probability that patients included in the study truly had CIDP. The PID algorithm is an iterative decision-making process that reviews each study candidate’s healthcare usage over time using the criteria described above. Claims for patients who met some, but not all, of the criteria for CIDP by the PID algorithm were subjected to manual review. Reviewers did not have access to lumbar puncture results, clinic notes, or results of nerve conduction studies/electromyography (EMG) studies. Patients identified as having CIDP were excluded if they denied the CIDP diagnosis when contacted by AHS. To prevent exclusion of patients with CIDP who were initially coded as acute inflammatory demyelinating polyneuropathy (AIDP), ICD-9 codes for both CIDP and AIDP were included in the PID algorithm. However, the diagnosis of CIDP required at least 8 weeks of treatment after initial diagnosis. Patient age was calculated as of June 30, 2011. The age–gender distribution of the study population with CIDP was determined by deciles of age in years and was performed for the overall study population and by gender. The relative prevalence MUSCLE & NERVE
July 2014
47
of comorbidities was determined from examination of diagnosis codes in medical claims. Psychiatric diagnoses included multiple mental health-related conditions (e.g., affective psychosis, adjustment disorder, anxiety disorder, attention deficit disorder, bipolar disorder, depression). Because a patient could have multiple comorbidities, the total for different comorbidities could exceed 100%. Determining the Health Plan Paid Costs and Major Cost Drivers. The total health plan paid costs were summarized by patient. The resulting amount was divided by the number of total member months and multiplied by 12 to determine per patient per year (PPPY) costs. The mean health plan paid cost PPPY was analyzed further by claim category and comorbidity burden. Health plan paid costs were categorized as a pharmacy or medical cost; paid amounts not identified as a pharmacy cost were considered to be a medical cost. Pharmacy costs included the health plan paid costs for prescription drugs billed using National Drug Code (NDC) codes and the costs for injectable drug claims billed using Healthcare Common Procedure Coding System (HCPCS) codes from multiple POS settings (e.g., pharmacies, physician offices, home infusions, outpatient hospital settings). Pharmacy claims billed using NDC codes were used to identify the top drug classes and the most frequently prescribed drug names. The costs for intravenous immunoglobulin (IVIg) were identified as described previously.5 To determine the principal drivers of healthcare costs, a POS category was assigned as described in Guptill et al.,6 except that the costs for injectable drugs billed using HCPCS codes and those for the prescription drugs billed using NDC codes were determined separately. Statistical Analysis. This study used data for all CIDP patients who met the inclusion criteria, and no sampling was done. The cost data were not Winsorized (a statistical technique to limit extreme values), and outliers were not removed. The mean health plan paid cost PPPY is presented with its standard error of the mean, ranges, and 95% confidence intervals (CI). For descriptive purposes, the associations between variables were measured using the correlation procedure of SAS version 9.1 (SAS Institute, Cary, NC). RESULTS
Among 6.5 million covered lives in 9 health plans, 233 patients with an ICD-9 code for CIDP were identified. Using the AHS PID algorithm, this group was reduced to 73 patients who met study entry criteria for the cost analysis. Patients were excluded because their health plan
Demographics.
48
Costs of CIDP
FIGURE 1. Age distribution (deciles of years) by gender in 73 patients with chronic inflammatory demyelinating polyneuropathy. There is a bimodal distribution, with peaks for women in the third and sixth deciles. Peaks for men occur in the fourth and sixth deciles.
was not eligible for the AHS care management program (n 5 73), no eligible claims were filed during the study (n 5 8), or the patient denied the CIDP diagnosis (n 5 75). Patients who died (n 5 4) were also not included. Forty-four percent were women, and 56% were men. The mean age was 47 years, and the median age was 51 years. Five patients (3 women and 2 men) were younger than 19 years, and 3 (1 woman and woman men) were older than 65 years. There was a bimodal age distribution with peak distributions in the third and sixth deciles for women and in the fourth and sixth deciles for men (Fig. 1). The majority (93%) of patients were covered by a commercial health plan, and 7% were covered by Medicaid. These patients had a total of 574 clinic visits, and the mean number of visits per patient was 8.4 6 1 (median 5, range 1–41). Eight patients had paid claims for nerve conduction or EMG studies. Seven patients had both nerve conduction and EMG studies, and a total of 18 nerve conduction study and 7 EMG units were performed on those 8 patients. Forty percent of the CIDP patients had none of the 30 defined comorbidities, while 19% had 1, and 41% had 2 or more comorbidities. No patient had more than 7 comorbidities. The five most prevalent comorbidities were hypertension (29%), hyperlipidemia (27%), diabetes (16%), psychiatric diagnosis (15%), and hypothyroidism (12%) (Table 1). Among drugs billed using NDC codes, the five most common prescription drug classes were anticonvulsants (33%), analgesic opioids (27%), antihyperlipidemics (27%), antihypertensives (26%), and antidepressants (25%). Within these drug classes, the most commonly used drugs included MUSCLE & NERVE
July 2014
Table 1. Comorbidities with a relative frequency of 5% among 73 CIDP patients. Comorbidity* Hypertension Hyperlipidemia Diabetes Psychiatric diagnoses Hypothyroidism Anemia Asthma Cancer Osteoarthritis Coronary artery disease Headache
Percentage with comorbidity 29 27 16 15 12 8 7 7 7 5 5
*Other comorbidities examined were congestive heart failure, chronic obstructive pulmonary disease, dementia, dysphagia, epilepsy, gastroesophageal reflux disease, irritable bowel syndrome, infectious diarrhea, interstitial lung, lactose intolerance, migraine, pulmonary hypertension, obesity, osteoporosis, pulmonary fibrosis, renal failure, skin infection, sleep disorder, and urinary tract infection.
gabapentin (26%), prednisone (16%), azithromycin (14%), amoxicillin (10%), and lisinopril (10%) (Table 2). Steroid-sparing agents, including mycophenolate mofetil and azathioprine, were used in
