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Chlamydia Screening in a Health Plan Before and After a National Performance Measure Introduction

Burstein, Gale R. MD, MPH; Snyder, Mark H. MD; Conley, Deborah MS; Newman, Daniel R. MA; Walsh, Cathleen M. DrPH; Tao, Guoyu PhD; Irwin, Kathleen L. MD, MPH

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doi: 10.1097/01.AOG.0000171119.81704.51
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Chlamydia trachomatis infection is a major health problem for adolescents and young adults. Studies in primary care and family planning clinics show infection rates of 5–14% for those aged 15–19 years and 3–12% for those aged 20–24 years (Walsh C, Irwin K. Combating the silent chlamydia epidemic. Contemp Ob/Gyn 2002;Apr:90–8). Up to 70% of genital chlamydial infections in females are asymptomatic and undetected (Walsh and Irwin, 2002). Because untreated chlamydial infection may result in pelvic inflammatory disease and its sequelae, including tubal-factor infertility, ectopic pregnancy, and chronic pelvic pain (Walsh and Irwin, 2002),1,2 the screening of asymptomatic young women for chlamydia is a simple, cost-effective intervention that significantly reduces the incidence of adverse sequelae.1,3,4 Routine chlamydia screening for sexually active adolescent and young adult females is recommended by several national organizations.5–10 The U.S. Preventive Services Task Force ranks chlamydia screening as one of the top 10 preventive services recommended for adolescents and adults in terms of disease burden prevented and cost-effectiveness.11

In 2000, the National Committee for Quality Assurance (NCQA), a private, not-for-profit organization that monitors the quality of health plans, introduced a new Health Plan Employer Data and Information Set (HEDIS) performance measure to determine the proportion of sexually active adolescent and young adult female members of Medicaid and commercial health plans that are tested annually for chlamydia. Health Plan Employer Data and Information Set is a set of performance measures voluntarily reported by health plans and used by NCQA to measure the quality of care and level of service in health plans. The new data set allows health insurance purchasers and consumers to compare health plan performance and enables health plans to benchmark their performance. The HEDIS Chlamydia Screening Measure estimates the proportion of sexually active female plan members, aged 16–25 years, who were continually enrolled in the previous year and who had at least one test for chlamydia during that year.

Since introducing this measure, Medicaid and most commercial health plans have reported persistently low proportions of eligible females who were chlamydia-tested; in 2002, a mean of 41% of eligible Medicaid plan enrollees and 25% of eligible commercial plan enrollees were tested.12 The reported proportions of eligible females who were tested for chlamydia have been substantially lower those in their other reports of preventive and therapeutic services as measured by HEDIS.12

Although HEDIS is only a measure to estimate performance, it is consistent with chlamydia-screening guidelines of various national organizations. Many health plans attempt to change practices to improve treatment and to improve their performance ratings. To estimate the new performance measure's association with change in clinical practice, we examined differences in a large commercial health plan's proportion of eligible females tested, burden of infection, and policies and procedures of specialty departments before and after introduction of the chlamydia-screening HEDIS measure.

MATERIALS AND METHODS

Kaiser Permanente Mid-Atlantic States (KPMAS) is an employer-based, not-for-profit, managed care organization serving a racially and economically diverse population of approximately 500,000 members. Covered member benefits include health care services received from only KPMAS providers and facilities. All KPMAS providers function under the same organization and are asked to adhere to consistent standards of care. All KPMAS providers include board-eligible and board-certified specialists and subspecialists who practice in 25 ambulatory care sites in Baltimore, Washington, DC, and the surrounding Maryland and northern Virginia suburbs. During the period under review, Medicaid beneficiaries were not enrolled.

Adolescent KPMAS members have access to confidential adolescent primary and reproductive health care services. All KPMAS members may choose the specialty type of their primary care provider. All female members have unrestricted access to obstetrics and gynecology services; a primary care provider's referral is not required. Kaiser Permanente Mid-Atlantic States does not generate explanations of benefits, thereby avoiding automated disclosure to parents regarding sexual health services received. Clinic laboratories may perform urine pregnancy tests upon member request, regardless of member age, without a preceding clinical encounter, and at no additional cost. Consistent with state laws and regulations, the consent of the adolescent is required before KPMAS patient medical information related to reproductive health is released to parents, guardians, or outside providers.

The study sample included all female KPMAS members, 15–26 years of age, who were enrolled in the KPMAS health plan for at least 11 months per year from January 1, 1998, through December 31, 2001.

One of the authors (G.R.B.) interviewed chiefs of KPMAS departments of obstetrics and gynecology, pediatrics, internal medicine, and family practice. Department chiefs were asked a standard set of open-ended questions about departmental practice and policy changes that were instituted to increase chlamydia screening of sexually active 15- to 26-year-old female patients.

The KPMAS facilities are linked by a state-of-the-art, secure electronic medical data system. Because each KPMAS member is assigned a permanent and unique identifying number, the clinical, laboratory, and administrative records for any member can be retrieved at any KPMAS site. Linked databases include laboratory, radiology, pharmacy, nursing, membership, appointment, and clinician notes. The system can construct episodes of care using patient and provider characteristics, laboratory procedures and results, and other diagnosis and procedure codes using the International Classification of Diseases, 9th Revision (ICD-9) and Current Procedural Terminology.

The KPMAS medical data system was searched for all patient visits by 15- to 26-year-old females enrolled for at least 11 months per calendar year during the period January 1, 1998, through December 31, 2001. The following data were collected: member age as of December 31 of the analysis year, date of enrollment, provider specialty, chlamydia tests performed and subsequent results, and other reproductive health services received, such as Pap tests and pregnancy-related and contraception services. Data describing Kaiser Permanente member race and ethnicity were not available. During 1998–2001, the KPMAS Central Laboratory tested cervical specimens for chlamydia, using a DNA probe (GenProbe, San Diego, CA) according to the manufacturer's instructions. For each measurement year, chlamydia tests were identified using Current Procedural Terminology codes described in the HEDIS measure.13 Data were entered into a computer spreadsheet (Excel 2003; Microsoft, Redmond, WA) and analyzed using EPI Info 2000 (Centers for Disease Control and Prevention, Atlanta, GA).

To estimate the proportion of KPMAS 15- to 26-year-old female members who were eligible for chlamydia screening according to criteria for sexual activity defined by the HEDIS measure,13 we identified sexually active members using pharmacy and claims data for Pap tests, pelvic examinations, filled contraceptive prescriptions, pregnancy-related services, and screening and treatment for any sexually transmitted disease within each measurement year. We classified the provider specialty type that provided care to eligible female KPMAS members as 1) exclusively primary care (ie, care received from providers practicing in either a pediatrics, internal medicine, or family practice office), 2) exclusively obstetrics and gynecology, (ie, care received from providers practicing in a obstetrics and gynecology office), or 3) both primary care and obstetrics and gynecology (ie, care received by both providers practicing in a primary care office and providers practicing in an obstetrics and gynecology office). We classified Pap test, pregnancy test, and filled contraceptive prescription as categories of reproductive health services that may have been received at the time of chlamydia testing; these categories were not mutually exclusive.

The proportion of sexually active females tested for chlamydia and the proportion with positive test results were calculated for each measurement year. The proportion testing positive was calculated by dividing the number of females with a positive test result by the number of females tested. To evaluate differences in chlamydia testing, we used the Pearson χ2 test of independence to compare proportions screened during the 2 years before (1998 and 1999) and the 2 years after (2000 and 2001) the introduction of the chlamydia HEDIS measure. P < .05 was considered to be significant. To examine testing outcomes of adolescents and young adults separately, the proportion of chlamydia-tested females who tested positive was stratified by patient age (15–19 and 20–26 years).

The project protocol was approved by the Kaiser Permanente Northern California Institutional Review Board and was granted a nonresearch determination by the Centers for Disease Control and Prevention (CDC) Institutional Review Board.

RESULTS

All specialty departments that provided primary health care services to 15- to 26-year-old females reported having developed an explicit strategy for increasing chlamydia screening. The obstetrics and gynecology department instituted a policy to routinely collect a chlamydia test when a routine Pap test was performed on all 15- to 26-year-old female patients. Clinic assistants operationalized this policy by routinely placing a chlamydia collection swab next to the Pap test collection materials. The internal medicine and family practice departments advised providers at departmental meetings to perform chlamydia tests with Pap tests on 15- to 26-year-old female patients. The pediatrics department advised providers at departmental meetings and through written memoranda to perform chlamydia tests on all sexually active female patients aged 15 years or older, offered providers training that included information about chlamydia screening,8 and operated a subspecialty adolescent health care clinic. However, systems-level changes in clinical encounter protocols were not made by the internal medicine, family practice, or pediatrics departments.

The proportion of 15- to 26-year old females who were classified as sexually active remained constant over the 4 analysis years: 52% (37,438/71,927) during 1998–1999 and 52% (37,237/71,569) during 2000–2001 (Table 1). However, the proportion of eligible females tested for chlamydia increased from 1998–1999 to 2000–2001 (55% versus 72%; P < .001). The increase in proportion tested was greatest among females aged 20–26 years.

Table 1
Table 1:
Female Health Plan Members Classified as Sexually Active and Tested for Chlamydia, 1998–2001

Table 2 presents, by age group, the number of female members classified as sexually active who received each type of specialty care and the number who were tested for chlamydia. Among the subset of 15 to 26 year olds who had a clinical encounter during 1998–2001, the proportion seen by primary care and obstetrics and gynecology specialists did not vary substantially: 18% during 1998–1999 and 19% during 2000–2001 were seen exclusively by primary care specialists; 14% during 1998–1999 and 13% during 2000–2001 were seen exclusively by obstetrics and gynecology specialists; and 66% during 1998–1999 and 65% during 2000–2001 were seen by both primary care and obstetrics and gynecology specialists.

Table 2
Table 2:
Female Health Plan Members Who Received Care and Were Tested for Chlamydia trachomatis by Provider Specialty Type Before (1998–1999) and After (2000–2001) Introduction of the Chlamydia HEDIS Measure, by Age Groups

The proportion of eligible females tested for chlamydia in each measurement year varied by provider specialty type and time period (Table 2). Among eligible female members, 30% in 1998–1999 versus 32% in 2000–2001 (P < .001) who were seen exclusively by a primary care specialist, 57% in 1998–1999 versus 81% in 2000–2001 (P < .001) who were seen exclusively by an obstetrics and gynecology specialist, and 63% in 1998–1999 versus 84% in 2000–2001 (P < .001) who were seen by both primary care and obstetrics and gynecology specialists were tested for chlamydia.

Of those eligible for chlamydia testing, 84% during 1998–1999 (31,600/37,438) and 84% during 2000–2001 (31,404/37,237) were seen at least once by a primary care specialist, whereas 80% (29,858/37,438) during 1998–1999 and 79% (29,376/37,237) during 2000–2001 were seen at least once by an obstetrics and gynecology specialist (Table 2). However, of those tested for chlamydia, 27% (5,439/20,513) during 1998–1999 and 20% (5,354/26,730) during 2000–2001 were tested by a primary care specialist, whereas 85% (17,369/20,513) during 1998–1999 and 89% (23,756/26,730) during 2000–2001 were tested by an obstetrics and gynecology specialist (Table 2).

Among eligible patients receiving reproductive health services, the proportion tested for chlamydia increased after introduction of the chlamydia HEDIS performance measure; chlamydia tests were most frequently performed when a Pap test was performed (Table 3). The proportion of chlamydia-tested females increased from 1998–1999 to 2000–2001 among eligible patients who received a Pap test (from 64% to 87%, respectively; P < .001), who had a contraceptive prescription filled (from 53% to 74%, respectively; P < .001), and who received a pregnancy test (from 66% to 75%, respectively; P < .001). Increases in chlamydia-testing rates were appreciably higher among patients receiving a Pap or pregnancy test who were seen by an obstetrics and gynecology provider alone or by both obstetrics and gynecology and primary care providers (24.0% increase with Pap and 12.9% increase with pregnancy tests), compared with increases in chlamydia screening among patients who were seen by primary care providers alone (15.9% increase with Pap and 0% increase with pregnancy tests).

Table 3
Table 3:
Chlamydia trachomatis Tests Performed in Conjunction With Other Reproductive Health Services for Female Health Plan Members, 1998–2001

Even though more females were tested after the HEDIS measure was introduced, the proportion of females testing positive for chlamydia remained fairly constant. The proportion of females testing positive for chlamydia 2 years before the chlamydia HEDIS measure was 12.8% (974/7,623) among 15–19 year olds and 5.5% (707/12,948) among 20–26 year olds, yielding a total of 8% (1,681/20,571) testing positive among the eligible 15- to 26-year-old population. The proportion of females testing positive for chlamydia 2 years after the chlamydia HEDIS measure introduction remained high at 11.2% (996/8,906) among 15–19 year olds and 4.8% (856/17,895) among 20–26 year olds, yielding a total of 7% (1,852/26,801) testing positive among the eligible 15- to 26-year-old population. Regardless of age group and provider type seen, the proportion of females testing positive for chlamydia remained high (range 4.4–21.6%). Despite the small reduction in the proportion of females testing positive for chlamydia, a typical consequence of screening more patients, there was a 10% (n = 171) increase in the number of infections detected in the 2 years after the HEDIS measure introduction.

DISCUSSION

For this large commercial health plan, a policy that was operationalized through a simple clinical practice change in the obstetrics and gynecology department was followed by a 31% (from 55% to 72%) increase in the proportion of eligible female health plan members who were annually tested for chlamydia in the 2 years after the chlamydia HEDIS measure was introduced. The high proportion (74%) of eligible females chlamydia-tested in 2001 by KPMAS contrasts with the reported mean proportion of eligible females chlamydia-tested in 2001 by commercial health plans (26%) and Medicaid health plans (38%).14 Despite the increase in sexually active 15- to 26-year-old female patients tested at KPMAS, the proportion of females testing positive remained high, resulting in a 10% increase in the number of chlamydia-infected female patients identified.

Our findings suggest that a policy operationalized through a simple obstetrics and gynecology department clinical practice change was instrumental in increasing the proportion tested because testing increased most dramatically among the obstetrics and gynecology department providers who implemented this change. In addition, regardless of other reproductive health services provided, more testing by obstetrics and gynecology providers than by other specialty providers both before and after the practice change in this and other health care settings suggests that access to obstetrics and gynecology specialists for primary and preventive care may increase chlamydia screening.15

Such system-level changes in clinical practice design have proven effective in improving delivery of other ambulatory preventive services, such as childhood immunizations, pediatric developmental evaluation and referral, anticipatory guidance,16,17 prenatal human immunodeficiency virus (HIV) testing,18 and colorectal cancer screening in a general medicine clinic.19 Issuance of clinical guidelines and performance measures alone rarely change provider practices.20

Health-seeking behaviors of health plan members can be a barrier to achieving high proportions of chlamydia-tested females. Because an estimated 40% of KPMAS adolescent members receive no primary or preventive care, during which a Pap test and other preventive services may be offered,21 this systems-level change alone may not achieve very high screening coverage. For females who do receive preventive health care, increasing chlamydia screening by performing a chlamydia test with every Pap test will depend on the frequency of Pap tests. Three national organizations have recently issued recommendations that sexually experienced adolescent females should receive their first Pap test 3 years after coitarche and that sexually inexperienced females should receive a Pap test at age 21 years.22–24 However, adolescents younger than 21 years old have the highest reported rates of chlamydial infection.25 In settings in which Pap tests or pelvic exams are not performed, introduction of urine or self-collected vaginal specimens for chlamydia testing may facilitate routine chlamydia screening. Approximately one third of KPMAS adolescent patients who were tested for pregnancy were not tested for chlamydia (Table 3), a missed opportunity in which urine specimens could have been used for chlamydia testing.

At least 3 factors may have biased our estimates of chlamydia testing and positive test results. First, the use of administrative data to classify sexual activity may have resulted in 1) an underestimation of the number of sexually active female members compared with the use of patients' self-report and 2) a misclassification of sexual activity. This may have upwardly or downwardly biased our estimated proportion of sexually active females screened for chlamydia.14 Second, our estimated rate of positive chlamydia test results may be downwardly biased because the nonamplified DNA chlamydia probes used during this period are less sensitive than nucleic acid amplification chlamydia tests.5 The magnitude and effect on outcomes of these biases are unknown.

Several factors may limit the generalizability of our findings. First, chlamydia prevalence rates reported for the mid-Atlantic region of the United States are higher than rates reported for other U.S. regions.25 Health plans that serve populations in other regions of the United States that have lower chlamydia prevalence may not provide the same yield from screening or have similar baseline screening practices.26 Because we were unable to provide a complete demographic description of eligible KPMAS members because of the national Kaiser organization's policies on members' race/ethnicity documentation during the study period, our findings may not be generalizable to health plans serving members of a predominately specific demographic profile.

Second, the KPMAS-estimated chlamydia-testing rate before the HEDIS measure introduction was higher than the proportion of eligible females who were chlamydia tested as currently reported for most health plans.12,14 Other health plans, starting at different testing baselines, may have different experiences. In addition, KPMAS provides systems to ensure adolescent confidentiality for reproductive health care services that may promote elicitation of a sexual history and the offering and acceptance of chlamydia testing.27 Increasing chlamydia testing among sexually active adolescents may be challenging for health plans without adolescent confidentiality policies. Finally, KPMAS is a group-model health plan in which providers are asked to adhere to organizational practices and procedures. Most commercial plans are network-based, and independent providers have minimal obligation to adhere to standardized health plan protocols or practices.28 Thus, implementing and sustaining uniform systems-level changes may prove challenging.

Unlike a randomized controlled trial, our before-versus-after retrospective study design using historical controls cannot prove cause and effect. We were not able to determine whether other factors may have influenced providers' chlamydia-screening practices, such as increased awareness of high chlamydia prevalence rates among the eligible population or new medical professional organization chlamydia-screening guidelines. However, the obstetrics and gynecology department's structural intervention, where outcomes were not dependent on provider decision making, was highly correlated with our finding of increased chlamydia-screening rates.

In summary, following a new obstetrics and gynecology department policy in this health plan to couple chlamydia testing with routine Pap tests in response to the introduction of a chlamydia-screening HEDIS measure, the proportion of sexually active 15- to 26-year-old females tested for chlamydia increased overall by 31%; the proportion of females testing positive declined only 1%. Making simple systems-level changes and increasing access to obstetrics and gynecology providers appears to improve chlamydia-testing rates and increase asymptomatic infections detected in a commercial health plan. The proportion of positive chlamydia test results among our study's economically and racially diverse population was within the range reported from settings known to yield high chlamydia prevalence rates (Walsh and Irwin, 2002). The persistently high proportion of females testing chlamydia-positive in this commercial health care plan after the significant increase in the proportion of females tested warrants the screening of all young, sexually active, female health plan members.

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© 2005 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.