Gift, Thomas L. PhD; Owens, Chantelle J. MPH
CHLAMYDIA AND GONORRHEA ARE THE 2 most commonly reported diseases in the United States. They comprised approximately 80% of the episodes of diseases reported to the Centers for Disease Control and Prevention (CDC) in 2002.1 Approximately 3 million cases of chlamydial infection and 700,000 cases of gonorrhea are estimated to occur each year.2 A recent estimate suggests that the direct medical costs attributable to these 2 diseases and their sequelae are $625 million (in 2003 U.S. dollars); other estimates are higher.3,4 Most of these costs are attributable to sequelae of acute infection in women, primarily pelvic inflammatory disease (PID) and its sequelae. Because a high proportion of men and women infected with Chlamydia trachomatis and Neisseria gonorrhoeae lack symptoms, sequelae of undetected, untreated infection are common.5,6
Epididymitis and orchitis are the primary sequelae of acute chlamydia and gonorrhea in men and can lead to infertility; although both are relatively rare compared with sequelae of chlamydia and gonorrhea in women, epididymitis is more common than orchitis.7,8 Epididymitis has been estimated to develop in 1% to 5% of untreated chlamydial and gonococcal infections.9,10 In addition to C. trachomatis and N. gonorrhoeae, epididymitis and orchitis can be caused by Escherichia coli and other organisms, which may or may not be sexually transmitted.7
Estimates of the cost per episode of epididymitis in the United States have been published previously. Three were based on data or estimates of utilization that are 10 years old or more.9,11,12 More recent estimates were derived from Medicaid fee schedules from one state,13 based on charges from one hospital,14 or modeled from nationwide Medicaid payments.10 Adjusted to 2003 dollars, these prior estimates average $643 dollars per episode (Table 1).
The cost per episode of epididymitis and orchitis is an important variable in cost-effectiveness analyses of screening programs for chlamydia and gonorrhea in men. Cost-effectiveness analyses of screening in men typically include as benefits of screening some modeled impact of the intervention on infection rates in women (through reduced secondary transmission and partner services) and an estimate of averted epididymitis costs. Therefore, we sought to estimate the cost per episode of epididymitis and orchitis using recent medical claims data.
Materials and Methods
Data for this analysis were drawn from the MarketScan database (MEDSTAT Group, Ann Arbor, MI), which contains inpatient, outpatient, and pharmaceutical claims data from approximately 100 payers covering 4 million persons per year. Insured persons are employees and their dependents working with approximately 45 large employers and government organizations.
We examined data from 1998 and 1999, the 2 most recent years available to us when we began our study. We focused first on the outpatient data file and extracted those records featuring one of the following International Classification of Diseases, 9th Revision (ICD-9) diagnosis codes in either the primary or secondary field (the MarketScan outpatient file allowed for up to 2 diagnoses to be coded for each outpatient claim): 604, (which included 604.0, 604.90, 604.91, and 604.99), orchitis and epididymitis, 098.13 and 098.33, gonococcal epididymo-orchitis, acute or chronic.17 We did not include 016.40, epididymitis due to tuberculosis.
From the inpatient data file, we extracted all inpatient admissions that included one of the previously mentioned ICD-9 codes as a diagnosis. From these inpatient admission data, we excluded those admissions for which the ICD-9 reference to epididymitis or orchitis appeared to be incidental to the primary reason for the hospitalization. Because inpatient admissions could generate more than one claim, some listed more than 2 ICD-9 codes when all claims associated with the admission were examined together. However, the inpatient data also included a single primary ICD-9 code and a Diagnostic Related Group (DRG) code for each admission. All of the claims that featured one of the previously mentioned epididymitis or orchitis ICD-9 codes were assigned either DRG 339, testes procedures, nonmalignant or 350, inflammation of the male reproductive system. The remaining inpatient admissions that listed other ICD-9 codes as primary diagnoses (and in most instances, other DRG codes) were excluded. A complete list of excluded inpatient admissions that included any of the ICD-9 codes identified here is available from the authors on request.
We identified National Drug Codes (NDC) associated with the treatments for epididymitis, chlamydia, or gonorrhea recommended by the CDC in 1998.18,19 The 1998 CDC guidelines, released in January, were the guidelines that were in effect during the time covered by the claims data we examined. Using the U.S. Food and Drug Administration (FDA) NDC database, we identified any additional drugs for which claims were filed 20 or more times by patients who had outpatient or inpatient claims for epididymitis or orchitis. For those drugs that could be identified in this manner, we selected for possible inclusion in the cost estimate those that corresponded to FDA-approved treatments for epididymitis, chlamydia, gonorrhea, or for infection with E. coli, another organism that can cause epididymitis. Examples of additional drugs included through this process were cefpodoxime, sulfamethoxazole, and cephalexin. We also identified for possible inclusion claims for analgesics such as naproxen, ibuprofen, and oxycodone. A complete list of the drugs selected for analysis is provided in the Appendix. The MarketScan User Guide indicated that capitated drug plans were not represented in the drug claims database.20
We defined as one episode of epididymitis or orchitis either a single inpatient or outpatient claim or, if there was more than one claim for a given patient, any claims (inpatient or outpatient) that occurred with a gap of ≤60 days between claims. As an example, a patient who had an outpatient claim on March 1, a series of inpatient claims associated with a hospitalization occurring between April 1 and April 4, then another outpatient claim on April 10 would have all of those claims attributed to one episode. A patient with 2 outpatient claims between March 1 and April 1 and then another outpatient claim on August 1 would have the latter visit designated as a different episode of epididymitis or orchitis. We also examined intervisit gaps of 45 and 90 days.
To reduce the likelihood of estimation error that could be caused by epididymitis or orchitis episodes that received some care before January 1, 1998, or after December 31, 1999, the limits of our data, we included in our final analysis only those episodes for which the first epididymitis or orchitis claim appeared between July 1, 1998, and June 30, 1999.
Because we wanted to focus on men for whom epididymitis or orchitis would be most likely to be sexually transmitted, we categorized claims based on the age at the time of the first epididymitis or orchitis claim. We used 3 categories: <13 years of age, ≥13 and <41 years of age, and ≥41 years of age to determine if cost per episode differed significantly by age group.
The outpatient cost per episode was determined by summing the dollar value of all outpatient claims identified as being for epididymitis or orchitis using the procedure described here. The inpatient cost per episode was determined by summing the dollar value of all inpatient claims related to an admission.
We included drug claims if they were for one of the prescription drugs identified previously and if the date of the drug claim was ≤7 days before the first outpatient or inpatient claim or ≤14 days after the last outpatient or inpatient claim identified as being part of an epididymitis or orchitis episode. Not all patients, however, had insurance coverage for prescription drugs.
We tested for statistical significance by 2-sided t-tests for differences in average costs and by exact χ2 tests for differences in the proportion of patients having claims for various types of care.
All costs were adjusted to 2003 U.S. dollars using the medical care component of Consumer Price Index for All Urban Consumers.16
A total of 6,929 patients in the database had claims for care for epididymitis or orchitis during the time period specified. The number of patients, number of outpatient visits, number of outpatient visits per episode, and number of episodes per patient for each of the 3 age groups we examined are shown in Table 2. Also shown in Table 2 are the percentage of patients with prescription drug coverage and the percentage of patients with drug coverage having drug claims.
There were no statistically significant differences in episodes per patient across age groups, although patients ≥41 years of age had significantly more outpatient visits per episode than patients in the other 2 age groups (P <0.01). Inpatient claims were relatively rare: 1.2% or less of episodes in each age group had records of inpatient care. Of the 62 patients who had claims for inpatient care, 15 had no identifiable claims for outpatient care. The only significant difference among the age groups for inpatient care was that the percent of episodes receiving inpatient care in men ≥41 was greater than in men aged ≥13 and <41 years (P <0.05).
Although roughly half of the patients in each age group had prescription drug coverage (with no significant difference between age groups), prescription drug claims were more common among older men who had drug coverage: 51.5% of men ≥13 and <41 years of age (and 53.6% of men ≥41) had claims for prescription drugs compared with 19.7% of the patients <13 years of age (P <0.01).
The estimated cost per episode for outpatient care, inpatient care, prescription drugs, and the total medical costs for epididymitis and orchitis are shown in Table 3. The cost per episode shown for prescription drugs and inpatient care are the average costs incurred by those having claims only. Claims for ceftriaxone, a CDC-recommended treatment for gonorrhea and epididymitis, were rare overall but more commonly found in the outpatient claims database than the prescription drugs database. The total cost per episode shown for each age group is the average total cost per episode, including claims for outpatient care, prescription drugs (if any), and inpatient care (if any). Outpatient cost per episode was significantly higher for young men (<13 years, P <0.01) at $331 versus $202 for men ≥13 and <41 years of age. Although the average cost per episode for inpatient care varied between the 3 age groups, the differences were not significant. Prescription drug costs for those patients having drug claims were significantly different from men ≥13 and <41 years of age for both patients <13 years and those ≥41 years of age (P <0.01). The average total direct cost per episode for the treatment of men ≥13 and <41 years of age with epididymitis or orchitis was $242. The total cost per episode was higher for men <13 years of age (P <0.01) and for men ≥41 years of age ($291, P <0.05).
These results were robust about the size of intervisit gap used to define a given episode. A shorter gap (45 days) led to 2.2% more episodes being defined for the same number of outpatient visits than those calculated using a 60-day gap, and a longer gap (90 days) led to 2.6% fewer episodes than when using a 60-day gap. There were no significant cost differences per episode compared with those resulting from using a 60-day gap (results not shown).
We estimated costs for outpatient and inpatient care for epididymitis and orchitis that were similar to those published in other studies. However, our average cost per episode is lower as a result of a much lower rate of inpatient treatment than previously observed. In the age group of most interest, men ≥13 and <41 years of age, only 0.5% of episodes had claims for inpatient care, and even in the youngest age group, those <13 years of age, the rate of inpatient care was only 1.2%, still far lower than the 9% to 11% rate reported elsewhere. However, many of the prior studies listed in Table 1 based their inpatient rate on one study9 and used updated costs to calculate new estimates of the overall cost per case.
Our findings mirror recent claims-based research on the cost of care for PID, which also found a lower cost per episode than previously reported as a result of a lower rate of inpatient care than reported in previous estimates.21 Had we used an inpatient rate of 10%, our cost per case for men ≥13 and <41 years of age would have been $700, which is in line with the existing estimates.
Our results are subject to several limitations. First, we could not be certain that all cases of epididymitis or orchitis we assumed were attributable to sexually transmitted diseases (STDs) were in fact caused by STDs using the available claims data. Even searching the claims data for records of care for chlamydia, gonorrhea, nongonococcal urethritis, or similar diagnoses would not provide a satisfactory answer, because epididymitis and orchitis largely follow untreated STDs for which there will be no claims for care. An examination to determine which Current Procedures Terminology codes were identified in outpatient encounters, plus a check of the drug claims data, would provide some insight, but without laboratory results, which our data do not provide, we would still not have definitive information on the cause of each episode of epididymitis. We focused on men ≥13 and <41 years of age to capture the group most likely to have STD-caused epididymitis or orchitis.7 The cost estimate for men who were ≥41 years, the group less likely to have STD-related epididymitis or orchitis, show that the total cost per episode, although higher than for our target age range, was only approximately 20% more. What cost difference existed was mostly attributable to a higher rate of inpatient care for the older men. The cost per episode for outpatient care was nearly identical for men ≥13 and <41 years of age and men ≥41 years of age. Using a narrower age range such as men ≥15 years of age and <30 years of age to capture episodes of epididymitis and orchitis most likely attributable to sexual transmission would have yielded results similar to those reported (e.g., the outpatient cost per episode would have been $201 per episode and the average drug claim would have been $70). The cost per episode in males under 13 years old was substantially higher, although still below that of previous estimates, and was attributable to greater outpatient costs. The higher outpatient cost may be the result of a more intensive level of care being given in a pediatric setting compared with that for older men. Our data show that the higher outpatient cost per episode was not the result of more outpatient visits; the number of outpatient visits for patients <13 years of age was not significantly different from that of either older age group.
Our estimates might be biased as a result of data limitations. First, we were unable to distinguish between episodes of epididymitis and orchitis because of the nonspecificity of the applicable ICD-9 codes, although it is probable that most claims were for epididymitis care. It is also possible that some episodes of epididymitis or orchitis were missed as a result of clinician coding error or use of a less-specific ICD-9 code such as 608.9, unspecified disorder of male genital organs. Had all of these nonepididymitis and orchitis-identified visits been included in the cost totals reported in Table 3, the average total cost per episode would have increased by up to 18.3%.
Second, not all patients had prescription drug coverage. It is reasonable to assume that some of those lacking drug coverage self-paid for prescription drugs, but without generating an observable drug claim. Also, capitated drug plans were not represented in the database; it is probable some prescribed drugs were paid by capitated plans. Some patients were treated with ceftriaxone, and the claims for that care were almost exclusively included in their outpatient records. Some of these patients also had prescription drug claims for other medications, but some also lacked either drug coverage or other drug claims. If we had assumed that those without drug coverage incurred prescription drug costs equal to those with drug coverage (both in terms of the percentage of episodes in which a claim was filed and in the average cost per claim), the total cost per episode in Table 3 would have been higher by up to 8.9% or to $264 for men ≥13 and <41 years of age. However, this total cost per episode is still lower than previous estimates. If we had assumed all patients had incurred costs for prescription drugs equal to those with claims, the total cost per episode would have been $306 for men in the middle age group. Had we included both the possible missed prescription drug costs and the nonspecific ICD-9-coded visits described previously, the total cost per episode would have been approximately 45% higher. Even adding 45% to our total costs would leave them well below previously published estimates at approximately $350.
Similarly, we may have underestimated the rate of inpatient treatment because not all inpatient admissions that included care for epididymitis or orchitis were included in our analysis. To avoid overestimating the cost of care, we excluded inpatient episodes for which the primary ICD-9 code was not epididymitis or orchitis. On this basis, 43 inpatient admissions were excluded, most of which were in our oldest age range. Even if we had included all of these episodes, our percentage of episodes receiving inpatient care would have increased to only 2.8% overall and 0.8% in our middle age range of ≥13 and <41 years, still well below previous estimates.
These data indicate that the total direct medical costs attributable to epididymitis and orchitis that are incurred in the United States annually are low. There were an estimated 2.8 million new cases of chlamydia in 2000 and 718,000 cases of gonorrhea.2 A recent cost study estimated that 78% of chlamydia and 29% of gonorrhea cases in men were untreated and that epididymitis occurred in 3% of untreated cases of chlamydia and gonorrhea.3 Assuming an even distribution of each disease by gender would mean that approximately 33,000 cases of epididymitis or orchitis are attributable to chlamydia annually, and another 3,000 cases are attributable to gonorrhea. These may be overestimates if a majority of chlamydia or gonorrhea cases occur in women, but 36,000 cases of epididymitis or orchitis would impose a direct medical cost of STD-associated epididymitis and orchitis of only approximately $8.7 million annually (using the cost per case estimate for our middle age group). This is much lower than the estimated annual cost of PID of $2.3 billion (not all of which is attributable to bacterial STD infection).21
Because epididymitis and orchitis are relatively rare sequelae of chlamydial and gonococcal infection, the potential for averted direct medical costs of epididymitis and orchitis are not themselves enough to make chlamydia or gonorrhea screening programs in men cost-saving. The primary potential benefit of chlamydia and gonorrhea case detection and treatment in men is the potential to avert medical costs in women through reducing the likelihood of transmission from men who are treated and through partner services for infected and treated men. However, an accurate estimate of the cost of epididymitis and orchitis that reflects current care practices will more accurately estimate the true cost of averted outcomes in men who participate in STD prevention and control activities and aid in optimal resource allocation for chlamydia and gonorrhea prevention.
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APPENDIX. Prescripti...Image Tools