Using Spatial Analysis to Inform Community Immunization Strategies.

INTRODUCTION: Recent pertussis outbreaks in the United States suggest our response to local disease outbreaks (eg, vaccine-preventable Bordetella pertussis) may benefit from understanding and applying spatial analytical methods that use data from immunization information systems at a subcounty level. METHODS: A 2012 study on Denver, CO, residents less than 19 years of age confirmed pertussis cases and immunization information system records were geocoded and aggregated to the census tract (CT) level. An algorithm assessed whether individuals were up-to-date (UTD) for pertussis vaccines. Pearson, Spearman, and Kendall correlations assessed relations between disease incidence and pertussis vaccine coverage. Using spatial analysis software, disease incidence and UTD rates were spatially weighted, and smoothed. Global and local autocorrelations based on univariate Moran's I spatial autocorrelation statistics evaluated whether a CT's rate belong to a cluster based on incidence or UTD measures. RESULTS: Overall disease incidence rate was 116.8/100 000. Assessment of pertussis vaccination coverage was available for 90% of the population. Among 134 672 Denver residents less than 19 years old, 103 496 (77%) were UTD for pertussis vaccines. Raw correlation coefficients showed weak relationships between incidence and immunization rates due to the presence of outliers. With geospatial and clustering analysis, estimates and correlation coefficients were improved with statistically significant Moran's I values for global and local autocorrelations rejecting the null hypothesis that incidence or UTD rates were randomly distributed. With evidence indicating the presence of clusters, smoothed and weighted disease incidence and UTD rates in 144 CTs identified 21 CTs (15%) for potential public health intervention. CONCLUSIONS: Correlation of raw disease incidence and vaccine UTD rates in subcounty regions showed limited association, providing limited information for decision making. By assessing for clusters using spatial analysis methods, we identified CTs with higher incidence and lower immunization coverage for targeted public health interventions.

Association between provision of initial family planning services and unintended pregnancy among women attending an STD clinic.

BACKGROUND: Most sexually transmitted disease (STD) clinics focus solely on STD treatment and prevention. However, women seeking care are also at high risk for unintended pregnancy. We sought to examine the relationship between baseline demographic and clinical characteristics and incident pregnancy among women provided initial contraceptive services in an STD clinic. METHODS: Computerized record review of women attending an STD clinic who initiated contraception, were seen at least twice within a 4-year period (repeat attendees), and indicated no intention of pregnancy were included in these analyses. Associations between baseline demographic, behavioral, and clinical characteristics and incident pregnancy were assessed using multivariate logistic regression. RESULTS: Among 4617 women seen from 2003 to 2006, 710 (15%) were repeat attendees and 3907 (85%) were single attendees (seen only during a single year). Among the repeat attendees, 642 (90%) indicated no interest in pregnancy, of whom 124 (19%) had a subsequent pregnancy. Using multivariate analysis and controlling for age and race/ethnicity, incident pregnancy was associated with previous pregnancy (OR 2.57, 95% CI 1.63-4.04),

The association of adherence to antiretroviral therapy with healthcare utilization and costs for medical care.

BACKGROUND: The association between antiretroviral adherence, healthcare utilization and medical costs has not been well studied. OBJECTIVE: To examine the relationship of adherence to antiretroviral medications to healthcare utilization and healthcare costs. METHODS: A retrospective cohort study was conducted using data from 325 previously antiretroviral medication-naive HIV-infected individuals initiating first antiretroviral therapy from 1997 through 2003. The setting was an inner-city safety net hospital and HIV clinic in the US. Adherence was assessed using pharmacy refill data. The average wholesale price was used for prescription costs. Healthcare utilization data and medical costs were obtained from the hospital billing database, and differences according to quartile of adherence were compared using analysis of variance (ANOVA). Multivariate logistic regression was used to assess predictors of higher annual medical costs. Sensitivity analyses were used to examine alternative antiretroviral pricing schemes. The perspective was that of the healthcare provider, and costs were in year 2005 values. RESULTS: In 325 patients followed for a mean (+/- SD) 3.2 (1.9) years, better adherence was associated with lower healthcare utilization but higher total medical costs. Annual non-antiretroviral medical costs were $US 7,612 in the highest adherence quartile versus $US 10,190 in the lowest adherence quartile. However, antiretroviral costs were significantly higher in the highest adherence quartile ($US 17,513 vs $US 8,690), and therefore the total annual medical costs were also significantly higher in the highest versus lowest adherence quartile ($US 25,125 vs $US 18,880). In multivariate analysis, for every 10% increase in adherence, the odds of having annual medical costs in the highest versus lowest quartile increased by 87% (odds ratio 1.87; 95% CI 1.45, 2.40). In sensitivity analyses, very low antiretroviral prices (as seen in resource-limited settings) inverted this relationship - excellent adherence was cost saving. CONCLUSION: Better adherence to antiretroviral medication was associated with decreased healthcare utilization and associated costs; however, because of the high cost of antiretroviral therapy, total medical costs were increased. Combination antiretroviral therapy is known to be cost effective; lower antiretroviral costs may make it cost saving as well.

Durability of adherence to antiretroviral therapy on initial and subsequent regimens.

There is uncertainty regarding the durability of adherence to antiretroviral therapy. This study is a retrospective review of previously antiretroviral naïve patients initiating therapy between 1997 and 2002. Antiretroviral adherence was calculated using prescription refill data and was analyzed over time on an initial regimen and on sequential antiretroviral regimens. Three hundred forty-four patients were included. The median lengths of the first, second, and third regimens were stable at 1.7 years, 1.2 years, and 1.5 years, respectively (p = 0.10). In multivariate analysis the factor most significantly associated with earlier initial regimen termination was poor adherence. On an initial regimen, adherence decreased over time and declined most rapidly in patients with the shortest regimens (4 to <16 months, -43% per year), followed by patients with intermediate regimen duration (16 to <28 months, -19% per year), and then patients with longer regimens (>/=28 months, -5% per year). In patients progressing to a third regimen, there was a trend toward decreasing adherence over successive regimens. In conclusion, sequential antiretroviral regimens are of similar lengths, with adherence being highly associated with first regimen duration. Adherence decreases during an initial regimen and on sequential antiretroviral regimens. Effective and durable interventions to prevent declining adherence are needed.

Selective drug taking during combination antiretroviral therapy in an unselected clinic population.

OBJECTIVES: Multidrug therapy is necessary to achieve sustained viral suppression. Discordant adherence to individual components of a multidrug regimen may lead to adverse outcomes. METHODS: Antiretroviral-naive patients initiating therapy from 1997 through 2002 were included. Adherence for each antiretroviral was determined using pharmacy refill data. Selective drug taking was defined as > or =5% difference in adherence between 2 components of an antiretroviral regimen lasting at least 60 days. RESULTS: A total of 322 of 415 patients (78%) met inclusion criteria. Selective drug taking occurred in 47 of 322 patients (15%) and on 51 of 438 regimens (12%). Factors associated with selective drug taking were lower baseline CD4 lymphocyte count (adjusted odds ratio [AOR]: 1.3, 95% CI: 1.1 to 1.6 per 100 cell/microL decrease); 3 times daily dosing schedule (AOR: 4.1, 95% CI: 1.1 to 15.5); and the presence of significant adverse drug events (AOR: 2.9, 95% CI: 1.3 to 6.4). Regimens containing a fixed-dose combination dosage form were less likely to have selective drug taking (AOR: 0.5, 95% CI: 0.2 to 0.99). Outcomes independently associated with selective drug taking included earlier progression to a new AIDS-defining illness or death (hazard ratio: 2.3, 95% CI: 1.2 to 4.5). CONCLUSIONS: Selective drug taking was relatively common among patients taking combination antiretroviral therapy. The factor most closely associated with selective drug taking was the presence of an adverse drug event. Clinical outcomes appeared worse in patients with selective drug taking.

Initiating contraception in sexually transmitted disease clinic setting: a randomized trial.

OBJECTIVE: Our purpose was to determine the effectiveness of sexually transmitted disease (STD) clinic-initiated contraceptive care. STUDY DESIGN: Nonpregnant women (n=877) attending an urban STD clinic using either no contraception or only condoms were randomly assigned to either an intervention (n=437) or control group (n=440). Both groups received condoms with spermicide and a referral list of primary care providers (PCP) for ongoing reproductive health care, and the intervention group also received enhanced contraceptive counseling, initial provision of contraception, and facilitated referral to a PCP. Outcomes measured at 4-, 8-, and 12-month follow-up were transition to a PCP, effective contraceptive use (ECU), interval pregnancy, and STD. RESULTS: The median time to PCP transition was 79 days for the intervention group versus 115 days for the control group (P=.007). Rates of ECU were higher for the intervention group than for control group at the 4-month visit (50% vs 22%, P<.0001) as well as the 8-month visit, although in the intervention group ECU diminished over the course of the study. During follow-up, pregnancy outcomes were documented for 229 women (26.1%), for an overall pregnancy rate of 38.2 per 100 person-years of follow-up. Of the 159 pregnancies defined by patient self-report, 153 (96.2%) were described as unintended and 32 (20%) resulted in a therapeutic abortion. The pregnancy rate was 15% lower in the intervention (105/437, 24.0%) than the control group (124/440, 28.2%) (P=.16), but this difference was not statistically significant. CONCLUSION: The intervention helped women transition to a PCP and initiate ECU but did not significantly reduce the pregnancy rate. More intensive interventions are needed to prevent unintended pregnancy in this high-risk population.

Predicting pregnancy risk in women attending an STD clinic.

BACKGROUND: Although sexually transmitted disease (STD) clinics focus mainly on STD treatment and prevention, women attending these clinics are also at high risk for pregnancy. GOAL: To evaluate the relationship between certain demographic and behavioral characteristics and the probability of pregnancy in women attending an urban STD clinic. STUDY DESIGN: Non-contraceptive-using women in an STD clinic-initiated randomized controlled contraception study (n = 877) were interviewed at baseline, and incident pregnancies within 1 year of enrollment were measured. Association between baseline demographic and behavioral characteristics with incident pregnancy was assessed by chi-square analysis, and logistic regression was used to assess factors associated with an incident pregnancy. RESULTS: Among the 673 women (76.7%) for whom follow-up pregnancy information was available, 220 (32.7%) incident pregnancies occurred within 1 year. By logistic regression controlling for study assignment, incident pregnancy was associated with age < or =19 years (odds ratio [OR], 2.8; 95% CI: 1.5-5.2), previous abortion (OR, 3.1; 95% CI: 1.7-5.4), frequency of sexual encounters of at least once a week (OR, 1.8; 95% CI: 1.2-2.6), and having a chlamydial infection at the time of enrollment (OR, 1.8; 95% CI: 1.0-3.2). With a combination of demographic and behavioral characteristics correlated by univariate analysis with incident pregnancy (i.e., age < or =19 years, nonwhite race, high school/general equivalency diploma or less education, previous pregnancy, no use of birth control with last intercourse, sex at least once a week, previous abortion, > or =3 partners within the past month, and <17 years of age at first pregnancy), the cumulative risk of pregnancy with 6 or more of the 9 characteristics was 51%, compared with 25.6% for women with < or =5 characteristics. CONCLUSION: For this STD clinic population, a combination of demographic and behavioral characteristics was useful when combined for identifying a subgroup of women at higher risk for subsequent pregnancy. Targeted intervention by STD care providers should include the provision for both pregnancy and STD prevention counseling.