Longitudinal analysis of healthcare costs: a case study of patients with major depressive disorder treated with duloxetine

Abstract

Objective:

To develop and apply a longitudinal model that adjusts for pre-treatment covariates to examine the trajectory of healthcare costs in duloxetine patients with major depressive disorder (MDD).

Methods:

Retrospective healthcare cost data from Thomson Reuters Marketscan® Database included 10,987 patients with MDD, aged 18–64, receiving duloxetine at low (<60?mg/day), standard (60?mg/day), or high (>60?mg/day) initial doses. A linear mixed-effects model for repeated measures used dose, month, and dose*month as fixed effects and patient (dose) as a random effect, and adjusted for demographics, comorbidities, body system disorders, and prior medication history. Model goodness-of-fit was evaluated with R². Rates of change (slopes) were estimated from the fitted model and differences in the cost trajectory among dosing cohorts were tested using the F-test. Bootstrapping and propensity score (PS) stratification were conducted to provide sensitivity analyses.

Results:

Main effects and covariates were all significant (p?<?0.05). Adjustment by pre-treatment covariates greatly improved the model fit (R^2?=?0.43). The model revealed a significant increase in healthcare costs in the 6 months preceding and a significant decrease in the 6 months following duloxetine initiation for each initial dose cohort and the overall cohort (p?<?0.05). In both the pre- and post-treatment periods, the high initial-dose cohort had higher healthcare costs than standard or low initial-dose cohorts (p?<?0.05). Bootstrapping and PS stratification confirmed these test results.

Limitations:

The analyses performed here were based on non-randomized, observational data, and thus subject to potential biases due to unmeasured confounding.

Conclusions:

Longitudinal models, compared with conventional mean-based methods, provide better opportunities to assess changes in cost trajectory patterns around the time of changes in medical treatment. In insured patients with MDD started on duloxetine, healthcare costs increased before duloxetine initiation, perhaps signaling a clinical deterioration that led to a change in treatment strategy. Healthcare costs then decreased following duloxetine initiation.     

Economic burden associated with inadequate antidepressant medication management among patients with depression and known cardiovascular diseases: insights from a United States–based retrospective claims database analysis

Abstract

Aims: The current study examined the association between insufficient major depressive disorder (MDD) care and healthcare resource use (HCRU) and costs among patients with prior myocardial infarction (MI) or stroke.

Methods: This was a retrospective study conducted using the MarketScan Claims Database (2010–2015). The date of the first MI/stroke diagnosis was defined as the cardiovascular disease (CVD) index date and the first date of a subsequent MDD diagnosis was the index MDD date. Adequacy of MDD care was assessed during the 90 days following the index MDD date (profiling period) using 2 measures: dosage adequacy (average fluoxetine equivalent dose of ≥20?mg/day for nonelderly and ≥10?mg/day for elderly patients) and duration adequacy (measured as the proportion of days covered of 80% or higher for all MDD drugs). Study outcomes included all-cause and CVD-related HCRU and costs which were determined from the end of the profiling period until the end of study follow-up. Propensity-score adjusted generalized linear models (GLMs) were used to compare patients receiving adequate versus inadequate MDD care in terms of study outcomes.

Results: Of 1,568 CVD patients who were treated for MDD, 937 (59.8%) were categorized as receiving inadequate MDD care. Results from the GLMs suggested that patients receiving inadequate MDD care had 14% more all-cause hospitalizations, 4% more all-cause outpatient visits, 17% more CVD-related outpatient visits, 13% more CVD-related emergency room (ER) visits, higher per patient per year CVD-related hospitalization costs ($21,485 vs. $17,756), higher all-cause outpatient costs ($2,820 vs. $2,055), and higher CVD-related outpatient costs ($520 vs. $434) compared to patients receiving adequate MDD care.

Limitations: Clinical information such as depression severity and frailty, which are potential predictors of adverse CVD outcomes, could not be ascertained using administrative claims data.

Conclusions: Among post-MI and post-stroke patients, inadequate MDD care was associated with a significantly higher economic burden.     

Clinical comorbidities,treatment patterns,and healthcare costs among patients with fibromyalgia newly prescribed pregabalin or duloxetine in usual care

Abstract

Objective:

To assess comorbidities, pain-related pharmacotherapy, and healthcare resource use among patients with fibromyalgia (FM) newly prescribed pregabalin or duloxetine (index event) in usual care settings.

Methods:

Using the LifeLink? Health Plan Claims Database, patients with FM (International Classification of Diseases, Ninth Revision, Clinical Modification code 729.1X) were identified. Patients initiated on duloxetine were propensity score-matched with patients initiated on pregabalin (n?=?826; mean age [standard deviation] of 48.3 [9.3] years for both groups). Prevalence of comorbidities, pain-related pharmacotherapy, and healthcare resource use/costs were examined during the 12-month pre-index and follow-up periods.

Results:

Both patient groups had multiple comorbidities and a substantial pain-related and adjuvant medication burden. In the pregabalin group, use of other anticonvulsants decreased significantly (31.6% vs 24.9%), whereas use of serotonin-norepinephrine reuptake inhibitors (SNRIs; 16.5% vs 22.5%) and topical agents (10.1% vs 13.2%) increased in the follow-up period (p?<?0.01). In the duloxetine group, there were significant decreases in the use of other SNRIs (13.0% vs 5.7%), selective serotonin reuptake inhibitors (41.3% vs 21.7%), and tricyclic antidepressants (18.8% vs 13.2%), and an increase in the use of anticonvulsants (28.6% vs 40.1%; p?<?0.0001). There were significant increases (p?<?0.0001) in pharmacy and total healthcare costs in both cohorts, and a significant increase in outpatient costs (p?=?0.0084) in the duloxetine cohort from pre-index to follow-up. There were no significant differences in median total healthcare costs between the pregabalin and duloxetine groups in both the pre-index ($10,159 vs $9,556) and follow-up ($11,390 vs $11,746) periods.

Limitations:

Limitations of this study are typical of those associated with retrospective database analyses.

Conclusions:

Patients with FM prescribed pregabalin or duloxetine were characterized by a significant comorbidity and pain/adjuvant medication burden. Although healthcare costs increased in both groups, there were no statistically significant differences in direct healthcare costs between the two groups.     

Changes in healthcare resource use and costs associated with early versus delayed initiation of atypical antipsychotic adjunctive treatment in major depressive disorder

Aims: The study compared all-cause and major depressive disorder (MDD)-related healthcare resource use (HRU) and costs in patients with MDD treated with atypical antipsychotic (AAP) adjunctive therapy early or later in treatment.

Materials and methods: Adults with MDD and antidepressant treatment (ADT) who newly initiated adjunctive aripiprazole, brexpiprazole, lurasidone, or quetiapine between October 1, 2014 and September 30, 2015 were identified in the IQVIA Real-World Data Adjudicated Claims database; the index date was the date of the first AAP claim. Patients were stratified into three cohorts: AAP initiated in the first year (Y1); in the second year (Y2); and more than 2 years (Y3) of first ADT use. Within each cohort, HRU and costs were compared between the 12 months before and after the index date. Pre–post changes in HRU and costs were then compared between cohorts.

Results: Five hundred and six (36.7%) patients were categorized as Y1; 252 (18.3%) as Y2; and 622 (45.1%) as Y3. AAP use was associated with significantly decreased rates of all-cause and MDD-related hospitalization and emergency department visits, and increased rates of pharmacy fills and physician office visits; and the magnitude of changes was largest in cohort Y1. Cohort Y1 had the largest reductions in mean (±SD) all-cause medical costs per patient (?$10,496?±?$85,022, p?=?.015) compared to Y2 (?$2,474?±?$85,022, p?=?.572) and Y3 (?$472?±?$31,334, p?=?.823), mainly due to the reduction in hospitalization. After adjusting for differences in baseline characteristics, the largest reductions in hospitalization and medical costs were observed in cohort Y1. Similar increases in all-cause pharmacy costs were seen in all cohorts. A similar trend in costs was observed in MDD-related healthcare services.

Limitations and conclusions: AAP treatment was associated with reductions in all-cause and MDD-related medical costs, primarily in decreased hospitalization. The reductions were largest among patients who initiated treatment in the first year.     

Economic impact of using inhaled corticosteroids without prior exacerbation among elderly patients with chronic obstructive pulmonary disorder

Abstract

Objective:

To assess the economic impact of initiating inhaled corticosteroids (ICS) without evidence of prior exacerbation among elderly patients with chronic obstructive pulmonary disease (COPD) in the US.

Methods:

This retrospective study used administrative claims to identify newly diagnosed COPD patients between 1/1/2005 and 6/30/2006 who were dispensed ICS. The dispense date of the first ICS was set as the index date. Patients with prior diagnoses for asthma, cystic fibrosis, or lung cancer were excluded. Cohorts were constructed based on whether ICS therapy was concordant with recommended guidelines of having prior COPD exacerbation. Each COPD patient with prior exacerbation was matched to four patients without exacerbation based on age, gender, Charlson Comorbidity Index, and whether COPD diagnosis code was not elsewhere specified (i.e., 496). Multivariate regressions were estimated to assess the association between use of ICS therapy without prior exacerbation and total healthcare costs, controlling for demographics and clinical characteristics.

Results:

The study included 3650 patients: 730 with prior exacerbation and 2920 without prior exacerbation. Patients were 76 years of age and 54% were male. Those with prior exacerbation were more likely to have inpatient stays both prior to (74.4 vs. 44.1%, p?<?0.05) and following (37.0 vs. 33.1%, p?<?0.05) the index date. Controlling for patient characteristics, patients who were dispensed ICS without prior exacerbation had $1859 higher in total costs (p?<?0.05) compared to patients with prior exacerbation during the 12 months following ICS initiation.

Limitations:

The retrospective design of this study limits the interpretation of findings as association and not causality. This study is subject to selection bias due to unobservable confounders.

Conclusions:

Among COPD patients, initiation of ICS without prior exacerbation appears to be associated with increased healthcare costs. These findings suggest that ICS initiation without evidence of exacerbation as consistent with guidelines is associated with adverse economic consequences.     

Treatment patterns and healthcare costs among newly-diagnosed patients with chronic myeloid leukemia receiving dasatinib or nilotinib as first-line therapy in the United States

Objective: To compare treatment patterns and economic outcomes of dasatinib and nilotinib as 1st-line therapies for chronic myeloid leukemia (CML).

Methods: Adult CML patients initiated on first-line dasatinib or nilotinib in 2010–2014 were identified from two large US administrative claims databases. Treatment patterns, tyrosine kinase inhibitor (TKI) adherence and healthcare resource utilization (HRU) and costs were measured from the 1st-line TKI initiation (index date) to the end of follow-up.

Results: A total of 604 and 418 patients were included in the dasatinib and nilotinib cohorts (mean ages = 50.9 and 52.5 years, 46.4% and 45.7% female), respectively. Among the dasatinib patients, 91% started with 100?mg/day, 3% with <100?mg/day, and 6% with >100?mg/day. Among the nilotinib patients, 76% started with 600?mg/day, 16% with >600?mg/day, and 8% <600?mg/day. The dasatinib cohort had a higher hazard of dose decrease (hazard ratio [HR]?=?1.66; p?=?.002) and of switching to another TKI (HR =1.62; p?=?.019) compared to the nilotinib cohort. The hazard of dose increase (HR =0.76; p?=?.423) and treatment discontinuation (HR =1.10; p?=?.372) were not significantly different between cohorts. There was also no significant difference in TKI adherence levels (mean proportion of days covered [PDC] difference over first 6 months = ?0.0003, p?=?.981; mean PDC difference over first 12 months = ?0.0022, p?=?.880) and HRU (inpatient day incidence rate ratio [IRR]?=?1.03, p?=?.930; emergency room IRR =1.26, p?=?.197; and days with outpatient services IRR = 1.01, p?=?.842). The dasatinib cohort incurred higher healthcare costs by $749 per patient per month (p?=?.044) compared to the nilotinib cohort.

Limitation: Information on CML phase and Sokal score was not available.

Conclusions: Dasatinib was associated with an increased hazard of dose decrease and switching to another TKI and higher healthcare costs, vs nilotinib.     

The cost-effectiveness of solifenacin vs. trospium in the treatment of patients with overactive bladder in the German National Health Service

Objective:

To carry out a cost–utility analysis comparing initial treatment of patients with overactive bladder (OAB) with solifenacin 5?mg/day versus either trospium 20?mg twice a day or trospium 60?mg/day from the perspective of the German National Health Service.

Methods:

A decision analytic model with a 3 month cycle was developed to follow a cohort of OAB patients treated with either solifenacin or trospium during a 1 year period. Costs and utilities were accumulated as patients transitioned through the four cycles in the model. Some of the solifenacin patients were titrated from 5?mg to 10?mg/day at 3 months. Utility values were obtained from the published literature and pad use was based on a US resource utilization study. Adherence rates for individual treatments were derived from a United Kingdom general practitioner database review. The change in the mean number of urgency urinary incontinence episodes/day from after 12 weeks was the main outcome measure. Baseline effectiveness values for solifenacin and trospium were calculated using the Poisson distribution. Patients who failed second-line therapy were referred to a specialist visit. Results were expressed in terms of incremental cost–utility ratios.

Results:

Total annual costs for solifenacin, trospium 20?mg and trospium 60?mg were €970.01, €860.05 and €875.05 respectively. Drug use represented 43%, 28% and 29% of total costs and pad use varied between 45% and 57%. Differences between cumulative utilities were small but favored solifenacin (0.6857 vs. 0.6802 to 0.6800). The baseline incremental cost–effectiveness ratio ranged from €16,657 to €19,893 per QALY.

Limitations:

The difference in cumulative utility favoring solifenacin was small (0.0055–0.0057 QALYs). A small absolute change in the cumulative utilities can have a marked impact on the overall incremental cost-effectiveness ratios (ICERs) and care should be taken when interpreting the results.

Conclusion:

Solifenacin would appear to be cost-effective with an ICER of no more than €20,000/QALY. However, small differences in utility between the alternatives means that the results are sensitive to adjustments in the values of the assigned utilities, effectiveness and discontinuation rates.     

Economic evaluation of duloxetine as a first-line treatment for painful diabetic peripheral neuropathy in Mexico

Abstract

Objective:

To perform an economic evaluation of duloxetine, pregabalin, and both branded and generic gabapentin for managing pain in patients with painful diabetic peripheral neuropathy (PDPN) in Mexico.

Research design and methods:

The analysis was conducted using a 3-month decision model, which compares duloxetine 60?mg once daily (DUL), pregabalin 150?mg twice daily (PGB), and gabapentin 600?mg three-times daily (GBP) for PDPN patients with moderate-to-severe pain. A systematic review was performed and placebo-adjusted risk ratios for achieving good pain relief (GPR), adverse events (AE), and withdrawal owing to intolerable AE were calculated. Direct medical costs included drug acquisition and additional visits due to lack of efficacy (poor pain relief) or intolerable AE. Unit costs were taken from local sources. Adherence rates were used to estimate the expected drug costs. All costs are expressed in 2010 Mexican Pesos (MXN). Utility values drawn from published literature were applied to health states. The proportion of patients with GPR and quality-adjusted life years (QALY) were assessed.

Results:

Branded-GBP was dominated by all the other options. PGB was more costly and less effective than DUL. Compared with branded-GBP and PGB, DUL led to savings of 1.01 and 1.74 million MXN (per 1000 patients). The incremental cost per QALY gained with DUL used instead of generic-GBP was $102 433 MXN. This amount is slightly lower than the estimated gross domestic product per capita in Mexico for 2010. During a second-order Monte Carlo simulation, DUL had the highest probability of being cost-effective (61%), followed by generic-GBP (25%) and PGB (14%).

Limitations:

Study limitations include a short timeframe and using data from different dosage schemes for GBP and PGB.

Conclusions:

This study suggests that DUL provides overall savings and better health outcomes compared with branded-GBP and PGB. Administering DUL rather than generic-GBP is a cost-effective intervention to manage PDPN in Mexico.     

Real-world rates,predictors, and associated costs of hypoglycemia among patients with type 2 diabetes mellitus treated with insulin glargine: results of a pooled analysis of six retrospective observational studies

Abstract

Objective:

To evaluate the real-world rates of hypoglycemia and related costs among patients with type 2 diabetes mellitus (T2DM) who initiated insulin glargine with either a disposable pen or vial-and-syringe.

Methods:

Pooled data were evaluated from six previously published, retrospective, observational studies using US health plan insurance claims databases to investigate adults with T2DM who initiated insulin glargine. The current study evaluated baseline characteristics, hypoglycemic events, and costs during the 6 months prior to and 12 months following insulin glargine initiation. Comparisons were made between patients initiating treatment with a disposable pen (GLA-P) and vial-and-syringe (GLA-V). Multivariate analyses using baseline characteristics as covariates determined predictors of hypoglycemia after initiating insulin glargine.

Results:

This study included 23,098 patients (GLA-P: 14,911; GLA-V: 8187). Overall annual prevalence of hypoglycemia was low (6.3% overall, 2.2% related to hospital admission or emergency department visit). Prevalence was significantly lower with GLA-P (5.5% vs 7.7%; p?<?0.0001). Furthermore, average glycated hemoglobin HbA1c reduction was higher with GLA-P (?1.22% vs ?0.86%; p?=?0.0012). The average annual hypoglycemia-related cost associated with initiating insulin glargine was $293, with GLA-P being 46% lower than GLA-V ($225 vs $417; p?=?0.001). Patients who had already developed microvascular complications at the time of initiating insulin therapy were at higher risk for developing hypoglycemia.

Limitations:

This study is limited by the use of retrospective data and ICD-9-CM codes, which are subject to coding error. In addition, this pooled analysis used unmatched cohorts, with multivariate regression analyses employed to adjust for between-group differences. Finally, results describe a managed care sample and cannot be generalized to all patients with T2DM.

Conclusions:

Patients with T2DM initiating insulin glargine treatment showed low rates of hypoglycemia, especially when using a disposable pen device. Hypoglycemia-related costs were low, contributing a very small proportion to overall diabetes-related healthcare costs.     

Anxiety disorders,major depressive disorder and the dynamic relationship between these conditions: treatment patterns and cost analysis

Abstract

Objective: To determine the treatment pattern and impact on healthcare costs of anxiety disorders and major depressive disorder (MDD), and influence of their concomitance and subsequence.

Methods: A retrospective cohort study was conducted using a US reimbursement claims database. Adult patients with an incident diagnosis of anxiety or MDD (index date) were included. Their sociodemographic data, diagnoses, healthcare resource use and associated costs were collected over the 6 months preceding and 12 months following index date.

Results: A total of 599,624 patients were identified and included. Patients with phobia or post-traumatic stress disorder had the highest 12-month costs ($8,442 and $8,383, respectively). Patients with social anxiety disorder had the lowest costs ($3,772); generalized anxiety disorder ($6,472) incurred costs similar to MDD ($7,170). Costs were substantially increased with emergence of anxiety during follow-up in MDD patients ($10,031) or emergence of MDD in anxiety patients ($9,387). This was not observed in patients with both anxiety and MDD at index date ($6,148).

Conclusion: This study confirms the high burden of costs of anxiety, which were within the same range as MDD. Interestingly, the emergence of anxiety or MDD in the year following a first diagnosis of MDD or anxiety, respectively, increased costs substantially. Major limitations were short follow-up and lack of absenteeism costs.     

Cost-effectiveness analysis of solifenacin versus oxybutynin immediate-release in the treatment of patients with overactive bladder in the United Kingdom

Abstract

Objective:

To carry out a cost-utility analysis comparing initial treatment with solifenacin 5?mg/day vs oxybutynin immediate-release (IR) 15?mg/day for the treatment of patients with overactive bladder (OAB) from the perspective of the UK National Health Service (NHS).

Methods:

A Markov model with six health states was developed to follow a cohort of OAB patients treated with either solifenacin or oxybutynin during a 1-year period. Costs and utilities were accumulated as patients transited through the health states in the model and a drop-out state. Some of the solifenacin patients were titrated from 5?mg to 10?mg/day at 8 weeks. A proportion of drop-out patients were assumed to continue treatment with tolterodine ER. Utility values were obtained from a Swedish study and pad use was based on a multinational clinical trial. Adherence rates for individual treatments were derived from a UK database study. For pad use and utility values, the drop-out state was split between those patients who were no longer receiving treatment and those on second-line therapy. Patients on second-line therapy who drop-out were referred for a specialist visit. Results were expressed in terms of incremental cost-utility ratios.

Results:

Total annual costs for solifenacin and oxybutynin were £504.30 and £364.19, respectively. First-line drug use represents 49% and 4% of costs and pad use represent 23% and 40% of costs for solifenacin and oxybutynin, respectively. Differences between cumulative utilities were small but were greater for solifenacin (0.7020 vs 0.6907). The baseline incremental cost-effectiveness ratio was £12,309/QALY.

Conclusion:

Under the baseline assumptions, solifenacin would appear to be cost-effective with an incremental cost-utility of less than £20,000/QALY. However, small differences in utility between the alternatives and the large number of drop-outs means that the results are sensitive to small adjustments in the values of utilities assigned to the drop-out state.     

The cost-effectiveness of pregabalin in the treatment of fibromyalgia: US perspective

Abstract

Objective:

To evaluate the cost-effectiveness of pregabalin in the treatment of fibromyalgia in a US patient population.

Methods:

A decision-analytic model was developed comparing pregabalin 150?mg twice a day (BID) and pregabalin 225?mg BID to placebo, duloxetine, gabapentin, tramadol, milnacipran, and amitriptyline in patients with severe fibromyalgia (Fibromyalgia Impact Questionnaire score >59; pain score >6.5). The model estimated response rates for all treatments at 12 weeks based on three randomized trials with pregabalin and a systematic review of published randomized controlled trials. Response was categorized as ≥30% improvement in baseline pain score plus global impression of change rating of much improved or very much improved. After 12 weeks of treatment, responders to treatment entered a treatment Markov model in which response was maintained, lost, or treatment discontinued. The cost-effectiveness end-points were cost per responder at 12 weeks and 1 year. Resource use was estimated from published studies and costs were estimated from the societal perspective.

Results:

Over 12 weeks, total cost per patient was $229 higher with pregabalin 150?mg BID than placebo, whereas pregabalin 225?mg BID was $866 less costly than placebo. At 1 year, pregabalin was cost saving and more effective than placebo, duloxetine, tramadol, milnacipran, and gabapentin. Compared with amitriptyline, pregabalin was not cost-effective at both dosages, although when excluding old and methodologically weak studies of clinical effectiveness of amitriptyline, pregabalin 225?mg BID became cost saving and pregabalin 150?mg BID was cost-effective.

Limitations:

Comparisons between pregabalin and other active agents are based on indirect comparisons, not head-to-head trials, and so should be interpreted with caution. Limitations for comparators include an inability to access sub-group data, inconsistency of response definitions, inclusion of older trials, and absence of long-term studies.

Conclusions:

This model found pregabalin to be cost-effective in treating patients with severe fibromyalgia.     

A cost comparison of long-acting insulin analogs vs NPH insulin-based treatment in patients with type 2 diabetes using routinely collected primary care data from the UK

Abstract

Aim:

The aim of this analysis was to investigate total healthcare costs, HbA1c, and weight changes over a 36-month period in patients with type 2 diabetes initiated on NPH or long-acting insulin analogs.

Methods:

Electronic patient data from 479 general practices in the UK (THIN database) were examined for new users of glargine (n?=?794), detemir (n?=?252), or NPH insulin (n?=?430). Annualized healthcare costs and clinical outcomes in years 1, 2, and 3 following insulin initiation were quantified and compared with baseline, using ANOVA and linear regression models.

Results:

A significant difference (p?<?0.05) in total healthcare costs increases at year 1 vs baseline was observed between glargine and detemir, detemir and NPH, but not between glargine and NPH (increase: +£486, +£635, and +£420 for glargine, detemir, and NPH users, respectively). However, increases by year 3 were not significantly different between the insulins. A propensity score analysis comparing analog and NPH insulin showed that, following insulin initiation, increases in costs were higher with insulin analogs at year one (+£220), but this difference decreased over time in each year following insulin initiation (+£168 and +£146, respectively, for years 2 and 3). HbA1c reductions were not significantly different between the groups at all time points. Differences in weight gain between glargine and NPH were statistically significant at year 1 (0.87?kg vs 1.11?kg) and year 3 (1.15?kg vs 1.57?kg), but other estimates of between-group differences in weight gain were non-significant.

Conclusions:

Following insulin initiation, the difference in healthcare costs of long-acting analogs compared to NPH insulin was transient. By year 3, the cost differences were not significantly different between the two cohorts, driven by an observed reduction in the cost of self-monitoring of blood glucose (SMBG) in the analog group and an increase in the cost of bolus insulin in the NPH group.