The 6-month persistence on SSRIs and associated economic burden

Figures & data

Figure 1.  Kaplan–Meier estimates of persistence with escitalopram, citalopram, fluoxetine, sertraline and paroxetine.

Table 1.  Patient baseline characteristics.

	Persistent users n = 8,609	Non-persistent users n = 36,872	p-value
Age, years, n (%)			<0.001
18–34	2,082 (24.2%)	12,415 (33.7%)
35–49	3,599 (41.8%)	14,520 (39.4%)
50–64	2,801 (32.5%)	9,340 (25.3%)
≥65	127 (1.5%)	597 (1.6%)
Gender (female), n (%)	6,126 (71.2%)	26,168 (71.0%)	NS
Region of residence, n (%)			<0.001
Northeast	1,056 (12.3%)	5,191 (14.1%)
South	1,838 (21.3%)	7,008 (19.0%)
Midwest	4,984 (57.9%)	20,016 (54.3%)
West	731 (8.5%)	4,657 (12.6%)
Physician specialty, n (%)			<0.001
GP/FP	3,579 (41.6%)	14,698 (39.9%)
Psychiatry	1,049 (12.2%)	4,919 (13.3%)
Internal medicine	1,732 (20.1%)	6,579 (17.8%)
Psychology	346 (4.0%)	1,485 (4.0%)
Neurology	28 (0.3%)	126 (0.3%)
Another	1,713 (19.9%)	8,192 (22.2%)
Missing/unknown	162 (1.9%)	873 (2.4%)
Type of healthcare plan			<0.001
Health maintenance organization (HMO)	3,587 (41.7%)	17,885 (48.5%)
Preferred provider organization (PPO)	3,025 (35.1%)	11,343 (30.8%)
Point of service (POS)	1,560 (18.1%)	5,726 (15.5%)
Indemnity	388 (4.5%)	1,628 (4.4%)
Consumer directed healthcare	0 (0.0%)	4 (0.0%)
Missing/unknown	49 (0.6%)	286 (0.8%)
Type of payer			<0.001
Commercial	8,069 (93.7%)	32,524 (88.2%)
Medicare risk	140 (1.6%)	672 (1.8%)
Medicare gap	2 (0.0%)	5 (0.0%)
Medicaid	172 (2.0%)	2,159 (5.9%)
Self-insured	198 (2.3%)	1,351 (3.7%)
Missing/unknown	28 (0.3%)	161 (0.4%)
Charlson index, mean ± SD	0.47 ± 1.69	0.48 ± 1.72	NS
History of depression, n (%)	2,476 (28.8%)	11,500 (31.2%)	<0.001
Anxiety at index date, n (%)	1,498 (17.4%)	6,667 (18.1%)	NS
Psychiatric co-morbidities, n (%)	4,671 (54.3%)	21,208 (57.5%)	<0.001
≥5 prescriptions before index date, n (%)	1,010 (11.7%)	3,515 (9.5%)	<0.001
AD prescribed at index date, n (%)			<0.001
Citalopram	587 (6.8%)	3,037 (8.2%)
Escitalopram	2,897 (32.5%)	10,930 (29.6%)
Fluoxetine	1,868 (21.7%)	7,533 (20.4%)
Paroxetine	1,259 (14.6%)	6,143 (16.7%)
Sertraline	2,098 (24.4%)	9,229 (25.0%)

NS, not significant.

Table 2.  Multivariate analysis of the variables associated with non-persistence at 6 months after index date: Cox model, analysis of maximum likelihood estimates.

	Hazard ratio [95% CI]
Type of antidepressant at index date
Escitalopram	1
Fluoxetine	1.005 [0.975; 1.035]
Sertraline	1.033 [1.005; 1.063]
Paroxetine	1.088 [1.054; 1.123]
Citalopram	1.102 [1.058; 1.148]
Age (years)
18–34	1
35–49	0.858 [0.837; 0.879]
50–64	0.923 [0.899; 0.948]
Physician’s specialty
GP/FP	1
Internal medicine	0.967 [0.940; 0.994]
Others	1.048 [1.022; 1.075]
Type of healthcare plan
Health maintenance organization (HMO)	1
Preferred provider organization (PPO)	0.890 [0.867; 0.914]
Point of service	0.896 [0.869; 0.924]
Indemnity	0.943 [0.895; 0.993]
Type of payer
Commercial	1
Medicare risk	1.213 [1.120; 1.315]
Medicaid	1.232 [1.172; 1.295]
Self-insured	1.264 [1.192; 1.339]
Region of residence
Midwest	1
South	1.042 [1.012; 1.074]
Northeast	1.089 [1.054; 1.126]
West	1.134 [1.094; 1.175]
Abuse before index date (vs. no abuse)
Drug abuse	1.126 [1.084; 1.170]
Alcohol-related disorders	1.137 [1.057; 1.223]
≥5 prescriptions before  index date (vs. <5)	0.886 [0.854; 0.919]
Drugs prescribed before index date (vs. no drugs prescribed)
Analgesics, anti-inflammatory	1.055 [1.030; 1.080]
Hypnotic	1.070 [1.034; 1.107]
Antianxiety	1.081 [1.054; 1.108]
Antipsychotic	1.112 [1.057; 1.169]
Analgesics, opioid	1.114 [1.071; 1.159]
Other antidepressants	1.394 [1.333; 1.458]
Same AD before index date and at index date (vs. different AD)	1.082 [1.043; 1.122]

Figure 2.  Healthcare costs (2003–2004 US$) (A) at baseline and (B) over the 6 months after the index date according to persistence status at 6 months after index date. Univariate statistical significance: *p < 0.05; **p < 0.01; ***p < 0.001.

Table 3.  Multivariate analysis of the variables associated with total healthcare costs (2003–2004 US$) after index date: generalized linear model (GLM) regression with log link and gamma distribution.

	RR [95% CI]	p-value
Non-persistence at 6 months	1.054 [0.999; 1.112]	0.055
Type of AD at index date
Escitalopram	1
Citalopram	1.037 [0.953; 1.128]	0.40
Fluoxetine	1.018 [0.958; 1.082]	0.56
Sertraline	1.087 [1.027; 1.151]	0.004
Paroxetine	1.079 [1.010; 1.151]	0.02
Age (years)
18–34	1
35–49	1.156 [1.099; 1.217]	<0.001
50–64	1.215 [1.152; 1.281]	<0.001
≥65	0.828 [0.503; 1.361]	0.46
Gender (male)	0.985 [0.940; 1.033]	0.53
Physician’s specialty
GP/FP	1
Psychiatry	1.264 [1.179; 1.355]	<0.001
Internal medicine	1.085 [1.022; 1.151]	0.008
Psychology	1.218 [1.090; 1.361]	<0.001
Others	1.174 [1.110; 1.240]	<0.001
Type of healthcare plan
Health maintenance organization (HMO)	1
Indemnity	0.832 [0.748; 0.926]	<0.001
Point of service	1.037 [0.974; 1.104]	0.26
Preferred provider organization (PPO)	1.130 [1.070; 1.192]	<0.001
Other	1.081 [0.815; 1.433]	0.59
Type of payer
Commercial	1
Medicaid	1.187 [1.064; 1.325]	0.002
Medicare risk	1.697 [1.058; 2.722]	0.03
Self-insured	0.825 [0.727; 0.937]	0.003
Other	0.925 [0.642; 1.333]	0.68
Region of residence
Midwest	1
Northeast	1.062 [0.992; 1.138]	0.08
South	0.894 [0.842; 0.950]	<0.001
West	0.839 [0.777; 0.905]	<0.001
Diagnosis of depression during 12 months before index date (vs. no diagnosis)	1.014 [0.966; 1.065]	0.56
Baseline psychiatric comorbidities
Anxiety disorders	0.990 [0.940; 1.043]	0.71
Others co-morbidities*	1.153 [1.091; 1.218]	<0.001
Bipolar disorder	1.164 [1.020; 1.328]	0.02
Drug abuse	1.199 [1.107; 1.299]	<0.001
Alcohol-related disorders	1.333 [1.141; 1.557]	<0.001
Schizophrenia	1.439 [1.031; 2.008]	0.03
Number of drug prescriptions during 12 months before index date
≥5	1.449 [1.322; 1.589]	<0.001
≥7	1.117 [0.975; 1.279]	0.11
Same AD before index date and at index date (vs. different AD)	0.973 [0.877; 1.080]	0.61
Drugs prescribed during 12 months before index date (vs. no drugs prescribed)
Antidepressant	0.994 [0.919; 1.076]	0.89
Antipsychotic	1.130 [1.010; 1.264]	0.03
Hypnotic	1.069 [0.996; 1.148]	0.06
Antianxiety	1.109 [1.050; 1.170]	<0.001
Antidepressants not under study	1.165 [1.054; 1.288]	0.003
Analgesics, anti-inflammatory	1.204 [1.147; 1.264]	<0.001
Analgesics, non-narcotic	1.096 [0.956; 1.257]	0.19
Analgesics, opioid	1.111 [1.023; 1.206]	0.01
Antiepileptics	1.221 [1.128; 1.322]	<0.001
Baseline Charlson comorbidity index	1.105 [1.088; 1.124]	<0.001
Baseline total healthcare cost	1.000 [1.000; 1.000]	<0.001

*Psychiatric comorbidities other than depression, anxiety disorders, alcohol-related disorders, drug abuse, bipolar disorders and schizophrenia.