The American Journal of Managed Care August 2011
Cost of Post-Traumatic Stress Disorder vs Major Depressive Disorder Among Patients Covered by Medicaid or Private Insurance
Objective: To compare healthcare costs and resource utilization among patients with post-traumatic stress disorder (PTSD) vs control subjects with major depressive disorder (MDD) in populations covered by Medicaid or private insurance.
Study Design: Retrospective analysis of Medicaid and private insurance administrative claims data.
Methods: Patients with at least 2 PTSD diagnoses during or after 1999, and at least 1 PTSD diagnosis during or after 2003, were identified from deidentified Medicaid claims from Florida, Missouri, and New Jersey (1999-2007) and from a privately insured claims database (1999-2008). Patients had continuous eligibility 6 months before (baseline) and 12 months after (study period) the index date and were aged 18 to 64 years. Potential control subjects having MDD without PTSD diagnosis were identified using similar selection criteria. Control subjects with MDD were matched to patients with PTSD on age, sex, state or region, employment status (private insurance only), index year, and race/ethnicity (Medicaid only). Study period per-patient utilization and costs, calculated as reimbursements to providers for medical services and prescription drugs, were compared using univariate and multivariate analyses.
Results: Patients with PTSD had higher rates of other mental health disorders (eg, anxiety and bipolar disorder) and higher mental health–related resource use and costs than control subjects with MDD in both Medicaid and privately insured populations. The mean study period total direct healthcare costs were higher for patients with PTSD than for control subjects with MDD ($18,753 vs $17,990 for Medicaid and $10,960 vs $10,024 for private insurance, P <.05 for both). The difference in total direct costs was driven by higher mental health–related resource use for patients with PTSD.
Conclusion: Patients having PTSD had 4.2% to 9.3% higher mean annual per-patient healthcare costs compared with matched control subjects having MDD among patients covered by Medicaid or private insurance.
(Am J Manag Care. 2011;17(8):e314-e323)
While post-traumatic stress disorder (PTSD) is common among Veterans Affairs (VA) patients, it is costly even to payers outside the VA system, including those covered by Medicaid or private insurance.
- A comparison of patients diagnosed as having PTSD vs demographically matched patients diagnosed as having major depressive disorder (MDD) suggests that patients with PTSD had 4.2% to 9.3% higher annual per-patient healthcare costs among patients covered by Medicaid or private insurance.
- Patients diagnosed as having PTSD had higher mental health–related resource utilization and costs compared with control subjects having MDD; the higher mental health–related costs were the primary driver of the cost difference.
The National Comorbidity Survey Replication estimated that the lifetime prevalence of PTSD is 6.8%, and the 12-month prevalence is 3.5% among general adults in the United States.2 Even after controlling for the type and degree of trauma, studies3,4 report that PTSD occurs approximately twice as frequently in women compared with men. Studies estimated high PTSD prevalence rates among military veterans (16.6%)5 and among urban primary care patients (23%).6 In contrast, analyses of mid to late 1990s Medicaid claims data estimated the annual prevalence of PTSD among the general adult US population to be much lower, at 0.4% to 0.5%,4,7 possibly because PTSD cannot be captured among individuals not seeking medical care.8
Post-traumatic stress disorder is associated with other psychiatric comorbidities, including substance abuse or dependence, major depressive disorder, panic disorder, agoraphobia, generalized anxiety disorder, obsessive-compulsive disorder, eating disorder, social phobia, and bipolar disorder.4,9,10 An analysis of the National Comorbidity Survey by Kessler8 suggested that PTSD may cause secondary mental health disorders: respondents with PTSD were more likely to develop anxiety, mood, and substance disorder than other respondents without PSTD, and the elevated risk of secondary mental health disorders disappeared with remission of PTSD. Post-traumatic stress disorder is associated with increased risk of congestive heart disease and with higher rates of hypertension, arthritis, asthma or bronchitis, kidney or liver disease, thyroid or autoimmune disease, stomach or gallbladder problems, epilepsy or neurologic disorders, and ulcers.10,11 The few studies12-14 describing healthcare utilization by patients with PTSD suggest that PTSD is associated with higher resource use relative to that by patients without any mental health disorders or by patients with non-PTSD mental health disorders. Compared with veterans without mental health diagnoses, veterans diagnosed as having PTSD had higher adjusted relative risk (aRR) of using primary care services (aRR, 1.3), medical or surgical subspecialty services (aRR, 1.6), ancillary services (aRR, 1.4), emergency services (aRR, 1.6), and inpatient services (aRR, 3.2).14 Few studies15,16 report healthcare costs of patients with PTSD in the United States. A study16 of female health maintenance organization members found that costs increased with increasing severity of PTSD symptoms; women having more severe PTSD symptoms had about twice the annual costs compared with women having less severe symptoms after adjusting for comorbidities and demographics ($3060 in 1997 US dollars among women with high scores, $1779 among women with median scores, and $1646 among women with low scores). Another study17 found that 12-month mental healthcare costs of patients having major depressive disorder (MDD) with PTSD were higher than those of patients having MDD without PTSD ($1196 vs $332).
Given the limited research available in the literature, the objective of the present study was to characterize the healthcare resource utilization and direct (medical and pharmaceutical) costs among patients with PTSD in Medicaid and privately insured populations. Based on the comorbidity burden and higher resource use reported in previous studies,4-16 it was expected that patients with PTSD would have higher costs compared with average patients without PTSD and that a more relevant comparison might be another well-studied mental health condition. Because depression often occurs after PTSD and the symptoms can overlap,18 the study sought to compare patients with PTSD vs matched control subjects with MDD, a well-characterized and costly population.19-22 The estimated lifetime prevalence of MDD among the adult US population is 16.2%, and the 12-month prevalence is 6.6%.21 The disorder is often comorbid with other psychiatric comorbidities. Among patients with lifetime prevalence of MDD, 72.1% had another mental health comorbidity, 59.2% had anxiety disorder, 24.0% had substance use disorder, and 30.0% had impulse control disorder.23 Annual healthcare costs per patient were estimated to be $8368 (in 1998 US dollars) among patients with treatment-resistant depression, $3571 among patients with depression that is not treatment resistant, and $2359 among a random sample of patients from a private insurance database.20
Two patient populations were analyzed in this study, one covered by Medicaid and the other by private insurance. The Medicaid study sample was selected from Medicaid claims databases in 3 states (Florida, Missouri, and New Jersey), covering approximately 12 million lives (1999-2007). The privately insured study sample was selected from a private insurance administrative database (Ingenix Employer Solutions, Rocky Hill, Connecticut) that included approximately 12 million beneficiaries (including employees, spouses, and dependents) from 55 large self-insured companies in the United States with claims for services provided from 1999 to 2008. Collectively, the companies have operations nationwide in a broad array of industries and job classifications.
The Medicaid and privately insured data contain deidentified information on patient demographics (eg, age and sex), monthly enrollment history, and medical and pharmacy claims. Medical services use was recorded, with dates of service, billed charges, actual amounts paid to providers, procedures performed (Current Procedural Terminology codes), and associated diagnoses (<9 codes for Medicaid data and <2 codes for privately insured data using the International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM]). The databases also include pharmacy claims, with prescribed medications identified by National Drug Code, date of prescription fill, days of supply, quantity, and actual payment amounts.
Patients were identified as having PTSD if they had at least 2 claims for PTSD (ICD-9-CM code 309.81) occurring on 2 different dates during or after 1999, with at least 1 claim for PTSD during or after 2003. Two PTSD diagnoses on 2 different dates were required to identify patients with PTSD. Because the duration of symptoms in patients who are receiving treatment is approximately 36 months and rises to 5 years or longer in patients not receiving treatment,24 the criterion of being positive for PTSD at 2 time points is an approximate validation of the diagnosis. The index date was defined as the first PTSD diagnosis during or after 2003 that was not the first overall PTSD diagnosis. To focus on prevalent rather than newly diagnosed patients with PTSD, the index date was selected as a PTSD diagnosis that was not the first PTSD diagnosis. Only patients with index dates starting in 2003 were selected so that healthcare resource use and costs reflected more recent treatment patterns. To ensure that complete claims data were available, patients with PTSD were required to have continuous healthcare coverage eligibility during the 6 months before the index date (baseline period) and during the 12 months following the index date (study period). Patients were required to be aged 18 to 64 years throughout the study period. Patients with PTSD having health maintenance organization, capitated, or Medicare coverage were excluded from the analysis because payment information may be incomplete for those patients.
Control subjects with MDD were selected using similar criteria. Controls included beneficiaries with no diagnosis of PTSD in the available data and with at least 2 claims for MDD (ICD-9-CM code 296.2 [MDD, single episode] or 296.3 [MDD, recurrent episode]) occurring on 2 different dates during or after 1999, with at least 1 claim for MDD during or after 2003. The index date for controls with MDD was defined as the first MDD diagnosis during or after 2003 that was not the first overall MDD diagnosis. Controls with MDD were also required to have continuous healthcare coverage eligibility during the 6 months before the index date (baseline period) and during the 12 months following the index date (study period), be aged 18 to 64 years throughout the study period, and have no health maintenance organization, capitated, or Medicare coverage. Note that this does not require the controls with MDD to have an MDD diagnosis during the 6-month baseline period.
Patients having PTSD were randomly matched one-toone to controls having MDD within each of the databases on age, sex, state or region, employment status (privately insured only), index year, and race/ethnicity (Medicaid only). Almost all (99.9%) identified patients with PTSD were matched to controls with MDD. Patients who were not matched were generally younger, in the range of 18 to 19 years.
Patients with PTSD and controls with MDD were compared on the following characteristics: demographics (age, sex, state or region, and race/ethnicity [the latter for Medicaid only]), employment status (privately insured only), and baseline rates of selected comorbidities over the 6-month baseline period. Baseline comorbidities included the following: mental health disorders, such as anxiety (excluding PTSD), bipolar disorder, depression (MDD or other depression), substance abuse or dependence, insomnia, and schizophrenia; chronic pain conditions, such as arthritis, back or neck pain, fibromyalgia, and migraine; and the Charlson Comorbidity Index (CCI), which includes 17 physical conditions predictive of 1-year mortality (including common conditions like cancer, diabetes mellitus, and cardiovascular disease).25,26
Healthcare costs, including medical service and prescription drug costs, were calculated for the 12-month study period. Cost analyses were conducted from the payer’s perspective (ie, costs were defined as Medicaid or private insurer payments to providers). Medical service costs were calculated for inpatient, emergency department (ED), and outpatient or other medical services. Prescription drug costs were calculated as mental health–related prescriptions (ie, antidepressants, antipsychotics, anxiolytics, anticonvulsants, and hypnotics or sedatives), cardiovascular drugs, antidiabetic drugs, gastrointestinal drugs, and other prescription drugs. Direct healthcare costs included both mental health–related and all-cause costs. Mental health–related costs included costs for mental health–related drugs, medical claims with a primary or secondary mental health disorder diagnosis (ICD-9-CM codes 290-319), and outpatient psychiatric treatment.
All costs were inflated to 2008 US dollars. These were obtained using the Consumer Price Index for medical care.