Cost analysis of a disease management programme for adult Medicaid clients with schizophrenia

Figures & data

Table 1. Baseline characteristics by group.

Characteristic	Disease management group (n = 73)	Propensity score-matched comparator group (n = 159)	Between-group differences (p-value)	Statistical significance
Age (mean (sd)) (years)	45.5 (9.5)	44.5 (12.0)	0.486	NS
Male gender (%)	63.0	59.1	0.317	NS
Race White (%)	73.9	67.9	0.869	NS
RxRisk (mean (sd))	5.0 (3.7)	5.4 (4.1)	0.496	NS
Baseline overall medical costs (mean PMPM (sd)) ($) *	908 (630)	1,196 (1667)	0.094	NS
Baseline overall pharmacy costs (mean PMPM (sd)) ($) *	623 (451)	521 (556)	0.624	NS
Propensity score (mean (sd)) ^†	0.149 (0.144)	0.114 (0.131)	0.079	NS

sd, standard deviation; NS, not statistically signifi cant at the ≤0.05 level; PMPM, per member per month.

* Between-group mean differences were assessed via two-sample t-test, log plus constant values.

^† Propensity score computed via a logistic regression that included age, gender, total baseline medical claim costs, total baseline pharmacy claim costs and the RxRisk case-mix risk adjustor.

Table 2. Median medical and pharmacy costs by group according to cost category.

Cost category	Disease management group		Propensity score-matched group
	Baseline	Post-intervention	Baseline	Post-intervention
Overall medical costs (median PMPM (25%, 75%)) ($)	1,050 (298, 1,263)	939 (184, 1,227)	554 (115, 1,443)	562 (105, 1,394)
Overall pharmacy costs (median PMPM (25%, 75%)) ($)	574 (277, 924)	618 (235, 900)	362 (148, 668)	338 (114, 755)

PMPM, per member per month.

Table 3. Pearson correlation matrix for continuous variables.

	Age	RxRisk	Log baseline medical costs	Log baseline pharmacy costs	Log post-medical costs	Log post-pharmacy costs
Age	1.000	0.054	-0.068	-0.149 *	-0.084	0.156
RxRisk	0.054	1.000	0.305 ^†	0.416 ^†	0.186 ^†	0.361 ^†
Log baseline medical costs	-0.068	0.305 ^†	1.000	0.443 ^†	0.755 ^†	0.378 ^†
Log baseline pharmacy costs	-0.149 *	0.416 ^†	0.443 ^†	1.000	0.335 ^†	0.815 ^†
Log post-medical costs	-0.084	0.186 ^†	0.335 ^†	0.335 ^†	1.000	0.514 ^†
Log post-pharmacy costs	-0.156 *	0.361 ^†	0.378 ^†	0.815 ^†	0.514 ^†	1.000

* Statistically significant at the 0.05 level;

^† statistically significant at the 0.01 level.

Table 4. Regression analysis of costs according to cost category.

Regression model and variables *	Coefficient	t-value	p-value	Adjusted R^2
Model 1: dependent variable, overall PMPM medical costs				0.575
Constant/intercept	0.782 ^$	2.50	0.013
Disease management group ^†	-0.358 ^$	-2.17	0.031
Baseline overall medical costs ^‡	0.871 ^¶	17.72	<0.001
Model 2: dependent variable, overall PMPM pharmacy costs				0.661
Constant/intercept	0.555 ^$	2.27	0.024
Disease management group ^†	0.031	0.16	0.870
Baseline overall pharmacy costs ^‡	0.876 ^¶	21.25	<0.001

PMPM, per member per month.

* All cost variables employed log plus constant transformations.

^† Coefficient interpreted as a percent reduction relative to the comparator group, where d is defined as the dichotomous treatment dummy variable:

^† Coefficient interpreted as a constant elasticity :%ΔY = β%ΔX.

^$ Statistically significant at the 0.05 level;

^¶ Statistically significant at the 0.01 level.

Table 5. Pre–post changes in costs among disease management clients according to cost category.

Cost category	Mean PMPM dollar change from baseline (pre) to disease management intervention (post)	Difference between zero (p-value)	Statistical significance
Overall medical costs (mean change (sd)) ($)	-14 (633)	0.733	NS
Overall pharmacy costs (mean change (sd)) ($)	15 (281)	0.425	NS

PMPM, per member per month; sd, standard deviation; NS, not statistically significant at the 0.05 level.

Table 6. Overall costs and claims by group according to organisation (ORGN) code.

ORGN code	Organisation description	Number of claims (overall)	Medical costs (overall)	Disease management group			Propensity score-matched comparator group
				Clients	Baseline	Post	Clients	Baseline	Post
5433	Home and community-based service—mentally ill	3,358	$757,429	51	$285,032	$403,408	9	$5,164	$63,825
5437	Home and community-based service—client services	3,883	$746,673	5	$24,521	$18,350	73	$46,180	$657,623
5439	Home and community-based service—persons with AIDS	41	$2,644	0	$0	$0	1	$113	$2,531
5452	Physician services and EPSDT	9	$109	0	$0	$0	2	$0	$109
5455	Physician services and EPSDT	107	$4,906	12	$357	$943	22	$616	$2,989
5457	Lab and X-ray	30	$536	3	$108	$474	5	$66	$287
5459	Dental services	6	$126	0	$0	$0	1	$0	$126
5460	Durable medical equipment	1,909	$165,927	10	$1,357	$8,305	81	$36,415	$119,849
5461	Emergency transportation	525	$6,701	11	$2,178	$419	15	$531	$3,573
5462	County transportation	2,902	$55,194	31	$8,838	$2,895	47	$4,168	$39,293
5475	Co-insurance (Title XVIII-Medicare)	10,875	$160,359	67	$11,462	$14,338	144	$24,468	$110,092
5481	School-based CL	18	$1,044	1	$108	$58	1	$0	$879
8159	HCBS-MI, CM	899	$65,612	52	$26,994	$25,972	10	$703	$11,943
8180	INPT PSYCH DHS	11	$47,275	0	$0	$0	1	$0	$47,275
	Total of claims with organisation coding	24,573	$2,014,535		$360,956	$474,763		$118,424	$1,060,393
	TCN-ICN to GL code missing	45,030	$4,055,515	73	$434,807	$256,184	159	$2,123,097	$1,241,427
	Grand total medical cost	69,603	$6,070,050		$795,763	$730,947		$2,241,521	$2,301,820

EPSDT, early prevention, screening and diagnostic testing; CL, community living; HCBS-MI, CM, home and community-based services for the elderly, blind and disabled case management; INPT PSYCH DHS, inpatient psychiatric care, Department of Human Services; TCN-ICN to GL, transaction control number-image control number to general ledger.