Using observational analysis of multiple sclerosis relapse to design outcomes-based contracts for disease-modifying drugs: a feasibility assessment

Figures & data

Table 1. Inclusion–exclusion criteria and sample size.

Inclusion–Exclusion Criteria
1. Pharmacy claim for a DMD between July 1, 2006, and March 31, 2009,^a with the first claim date identified as the index date and no DMD use in the previous 6 months (n = 26,612)
2. At least two medical claims with a primary or secondary diagnosis of MS (ICD-9-CM of 340.xx) from 6 months pre-index (i.e., the pre-period) through 24 months post-index (i.e., the post-period) (n = 24,509)
3. Aged 18–64 years on the index date (n = 23,702)
4. Continuous insurance coverage from the start of the pre-period through the end of the post-period (n = 2291)

^aThe study was based on claims with dates of service from January 1, 2006, through March 31, 2011. DMDs included glatiramer, interferon beta 1-a subcutaneous, interferon beta 1-a intramuscular, interferon beta 1-b, and natalizumab.

DMD, disease-modifying drug; ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification; MS, multiple sclerosis.

Table 2. Baseline patient characteristics of study cohort (n = 2291).

	Severe relapse requiring hospitalization (n = 333)	Moderate relapse requiring outpatient IVMP (n = 316)	No relapse (n = 1642)	p-value
Age (years; mean ± SD)	45.13 ± 11.51	42.65 ± 9.63	42.88 ± 10.29	<0.001
Gender (% Female)	77.8	80.7	78.2	0.579
Insurance product type (%)				0.003
EPO	17.1	18.4	16.3
HMO	8.7	9.5	9.3
Indemnity	2.7	1.0	0.6
POS	63.4	65.5	69.2
PPO	7.8	5.7	4.6
Other	0.3	0	0
Index DMD				0.286
Glatiramer	41.74	36.39	37.58
IFN beta 1-a IM	18.92	24.05	23.14
IFN beta 1-b	11.11	14.56	12.12
IFN beta 1-a SC	23.42	21.84	21.44
Natalizumab	4.80	3.16	5.72
CCI (mean ± SD)^a	0.84 ± 1.29	0.41 ± 0.76	0.41 ± 0.91	<0.001
Possible ADL impairment (%)^a,^b	53.2	42.7	36.6	<0.001
MS hospitalization (%)^a	21.0	9.5	10.3	<0.001
MS hospitalization or IVMP (%)^a	31.5	36.4	18.9	<0.001

^aPre-period measure of health status.

^bProxy measure that indicates whether patient had at least one condition (medical, psychosocial, musculoskeletal or dysphagia-related) suggesting possible ADL impairment. Source: Chan et al.27

ADL, activities of daily living; CCI, Charlson Comorbidity Index; DMD, disease-modifying drug; EPO, exclusive provider organization; HMO, health maintenance organization; IFN, interferon; IM, intramuscular; IVMP, intravenous methylprednisolone; POS, point-of-service; PPO, preferred provider organization; SC, subcutaneous; SD, standard deviation.

Table 3. Poisson regression analysis of number of severe relapses (n = 2291).

	Poisson model-estimated IRR	p-value
Age	1.013	0.019
Female relative to male	0.947	0.682
Geographic region relative to South
Northeast	0.992	0.966
Midwest	1.070	0.629
West	1.108	0.520
Insurance product type relative to indemnity/other^a
EPO	0.527	0.077
HMO	0.480	0.057
POS	0.468	0.027
PPO	0.724	0.401
Treatment relative to Glatiramer
IFN beta 1-a IM	0.823	0.202
IFN beta 1-b	0.756	0.133
IFN beta 1-a SC	0.979	0.881
Natalizumab	1.051	0.852
Pre-period health status
CCI	1.190	<0.001
Possible ADL impairment^b	1.353	0.009
MS hospitalization	1.701	<0.001
DMD MPR	0.155	<0.001

^aOne patient with ‘Other’ insurance was included in the indemnity group.

^bProxy measure that indicates whether patient had at least one condition (medical, psychosocial, musculoskeletal or dysphagia-related) suggesting possible ADL impairment. Source: Chan et al.27

ADL, activities of daily living; CCI, Charlson Comorbidity Index; DMD, disease-modifying drug; EPO, exclusive provider organization; HMO, health maintenance organization; IFN, interferon; IM, intramuscular; IRR, intensity (incidence) rate ratio; IVMP, intravenous methylprednisolone; MPR, medication possession ratio; MS, multiple sclerosis; POS, point-of-service; PPO, preferred provider organization; SC, subcutaneous.

Table 4. Logistic regression analysis of ≥1 severe relapse (n = 2291).

	Logistic model estimated odds ratio (95% CI)
Age	1.018 (1.005–1.031)
Female relative to male	0.919 (0.678–1.247)
Geographical region relative to South
Northeast	0.999 (0.644–1.548)
Midwest	1.133 (0.824–1.560)
West	1.137 (0.795–1.626)
Insurance product type relative to Indemnity/other^a
EPO	0.348 (0.131–0.919)
HMO	0.303 (0.110–0.837)
POS	0.297 (0.116–0.756)
PPO	0.529 (0.190–1.478)
Treatment relative to Glatiramer
IFN beta 1-a IM	0.773 (0.550–1.087)
IFN beta 1-b	0.696 (0.458–1.057)
IFN beta 1-a SC	0.952 (0.688–1.319)
Natalizumab	1.037 (0.569–1.890)
Pre-period variables
CCI	1.307 (1.166–1.464)
Possible ADL impairment^b	1.470 (1.134–1.905)
MS hospitalization	2.174 (1.537–3.074)
DMD MPR	0.101 (0.068–0.151)

^aOne patient with “Other” insurance was included in the indemnity group.

^bProxy measure that indicates whether patient had at least one condition (medical, psychosocial, musculoskeletal or dysphagia-related) suggesting possible ADL impairment. Source: Chan et al.27

CCI, Charlson Comorbidity Index; DMD, disease-modifying drug; EPO, exclusive provider organization; HMO, health maintenance organization; IFN, interferon; IM, intramuscular; IVMP, intravenous methylprednisolone; MPR, medication possession ratio; MS, multiple sclerosis; POS, point-of-service; PPO, preferred provider organization; SC, subcutaneous.

Table 5. Annualized adjusted all-cause healthcare charges (2012 US$) for patients with severe relapse requiring hospitalization or moderate relapse requiring outpatient IVMP.

Estimated Annual Mean (±SD) Charges (2012 US$)^a	Severe relapse requiring hospitalization (n = 333)	Moderate relapse requiring outpatient IVMP (n = 316)	p-value
Inpatient	$31,641 ± 10,207	$480 ± 538	<0.001
Emergency department	$54 ± 82	$40 ± 57	0.008
Home health	$991 ± 473	$953 ± 395	0.265
Physician office visit	$2776 ± 1434	$3079 ± 1332	0.006
Physical/Speech therapy	$111 ± 97	$51 ± 44	<0.001
Oral steroids	$3 ± 2	$2 ± 1	<0.001
IVMP	$19 ± 25	$188 ± 84	<0.001
Other^b	$12,666 ± 3821	$8742 ± 2078	<0.001
Total annualized charges	$48,173 ± 8665	$13,334 ± 1929	<0.001

^aCharges were estimated using a multivariate, generalized linear model with gamma distribution and log link. Regressions controlled for patient characteristics (age, sex, region of residence, and type of insurance coverage), year of index date, general health (Charlson Comorbidity Index), pre-period relapse, proxy for possible ADL limitation27, and index DMD.

^bAll services not included in (a)–(g), such as prescription drugs (other than steroids); laboratory tests; imaging, including magnetic resonance imaging (MRI); and outpatient surgeries and procedures, including those necessary to address bladder or bowel dysfunction.

DMD, disease-modifying drug; IVMP, intravenous methylprednisolone; SD, standard deviation.

Chan L, Shumway-Cook A, Yorkston KM, et al. Design and validation of a methodology using the International Classification of Diseases, 9th Revision, to identify secondary conditions in people with disabilities. Arch Phys Med Rehabil 2005;86:1065-9

 PubMed Web of Science ®Google Scholar