Ning Smith

Sociodemographic characteristics of members of a large, integrated health care system: comparison with US Census Bureau data.

BACKGROUND Data from the memberships of large, integrated health care systems can be valuable for clinical, epidemiologic, and health services research, but a potential selection bias may threaten the inference to the population of interest. METHODS We reviewed administrative records of members of Kaiser Permanente Southern California (KPSC) in 2000 and 2010, and we compared their sociodemographic characteristics with those of the underlying population in the coverage area on the basis of US Census Bureau data. RESULTS We identified 3,328,579 KPSC members in 2000 and 3,357,959 KPSC members in 2010, representing approximately 16% of the population in the coverage area. The distribution of sex and age of KPSC members appeared to be similar to the census reference population in 2000 and 2010 except with a slightly higher proportion of 40 to 64 year olds. The proportion of Hispanics/Latinos was comparable between KPSC and the census reference population (37.5% vs 38.2%, respectively, in 2000 and 45.2% vs 43.3% in 2010). However, KPSC members included more blacks (14.9% vs 7.0% in 2000 and 10.8% vs 6.5% in 2010). Neighborhood educational levels and neighborhood household incomes were generally similar between KPSC members and the census reference population, but with a marginal underrepresentation of individuals with extremely low income and high education. CONCLUSIONS The membership of KPSC reflects the socioeconomic diversity of the Southern California census population, suggesting that findings from this setting may provide valid inference for clinical, epidemiologic, and health services research.

Herpes zoster vaccine in older adults and the risk of subsequent herpes zoster disease.

CONTEXT Approximately 1 million episodes of herpes zoster occur annually in the United States. Although prelicensure data provided evidence that herpes zoster vaccine works in a select study population under idealized circumstances, the vaccine needs to be evaluated in field conditions. OBJECTIVE To evaluate risk of herpes zoster after receipt of herpes zoster vaccine among individuals in general practice settings. DESIGN, SETTING, AND PARTICIPANTS A retrospective cohort study from January 1, 2007, through December 31, 2009, of individuals enrolled in the Kaiser Permanente Southern California health plan. Participants were immunocompetent community-dwelling adults aged 60 years or older. The 75,761 members in the vaccinated cohort were age matched (1:3) to 227,283 unvaccinated members. MAIN OUTCOME MEASURE Incidence of herpes zoster. RESULTS Herpes zoster vaccine recipients were more likely to be white, women, with more outpatient visits, and fewer chronic diseases. The number of herpes zoster cases among vaccinated individuals was 828 in 130,415 person-years (6.4 per 1000 person-years; 95% confidence interval [CI], 5.9-6.8), and for unvaccinated individuals it was 4606 in 355,659 person-years (13.0 per 1000 person-years; 95% CI, 12.6-13.3). In adjusted analysis, vaccination was associated with a reduced risk of herpes zoster (hazard ratio [HR], 0.45; 95% CI, 0.42-0.48); this reduction occurred in all age strata and among individuals with chronic diseases. Risk of herpes zoster differed by vaccination status to a greater magnitude than the risk of unrelated acute medical conditions, suggesting results for herpes zoster were not due to bias. Ophthalmic herpes zoster (HR, 0.37; 95% CI, 0.23-0.61) and hospitalizations coded as herpes zoster (HR, 0.35; 95% CI, 0.24-0.51) were less likely among vaccine recipients. CONCLUSIONS Among immunocompetent community-dwelling adults aged 60 years or older, receipt of the herpes zoster vaccine was associated with a lower incidence of herpes zoster. The risk was reduced among all age strata and among individuals with chronic diseases.

Prevalence of Extreme Obesity in a Multiethnic Cohort of Children and Adolescents

OBJECTIVE To estimate the prevalence of extreme obesity in a large, multiethnic contemporary cohort of children and adolescents. STUDY DESIGN In a cross-sectional study, measured weight and height were extracted from electronic medical records of 710,949 patients aged 2 to 19 years (87.8% of eligible patients) who were enrolled in an integrated prepaid health plan in 2007 and 2008. Prevalence of extreme obesity was defined as body mass index (BMI)-for-age>or=1.2 times 95th percentile or BMI>or=35 kg/m2. RESULTS Extreme obesity was observed in 7.3% of boys and 5.5% of girls. The prevalence peaked at 10 years of age in boys and at 12 years of age with a bimodal distribution in girls (second peak at 18 years; P value for sex x age interaction=.036). The prevalence of extreme obesity varied in ethnic/racial and age groups, with the highest prevalence in Hispanic boys (as high as 11.2%) and African-American girls (as high as 11.9%). CONCLUSION Extreme obesity in Southern California youth is frequently observed at relatively young ages. The shift toward extreme body weights is likely to cause an enormous burden of adverse health outcomes once these children and adolescents grow older.

The association of psoriasis and elevated blood lipids in overweight and obese children.

OBJECTIVE To investigate whether obesity and cardiovascular risk factors are associated with psoriasis in children and adolescents. STUDY DESIGN For this population-based, cross-sectional study, measured weight and height, laboratory data, and psoriasis diagnoses were extracted from electronic medical records of 710,949 patients age 2 to 19 years enrolled in an integrated health plan. Weight class was assigned on the basis of body mass index-for-age. RESULTS The OR for psoriasis was 0.68, 1.00, 1.31, 1.39, and 1.78 (95% CI, 1.49 to 2.14) for underweight, normal-weight, overweight, moderately obese, and extremely obese children, respectively (P for trend < .001). The OR for psoriasis treated with systemic therapy or phototherapy as an indicator of severe or widespread psoriasis was 0.00, 1.00, 2.78, 2.93, and 4.19 (95% CI, 1.81 to 9.68) for underweight, normal-weight, overweight, moderately obese, and extremely obese children, respectively (P for trend < .003). In adolescents, mean total cholesterol, low-density lipoprotein cholesterol, triglycerides, and alanine aminotransferase were significantly higher in children with psoriasis compared with children without psoriasis after adjustment for body mass index. CONCLUSION Overweight and obesity are associated with higher odds of psoriasis in youths. Independent of body weight, adolescent patients with psoriasis have higher blood lipids. These data suggest that pediatricians and dermatologists should screen youths with psoriasis for cardiovascular disease risk factors.

Higher Prevalence of Obesity Among Children With Asthma

The aim of this study is to investigate the association between childhood obesity and asthma, and whether this relationship varies by race/ethnicity. For this population‐based, cross‐sectional study, measured weight and height, and asthma diagnoses were extracted from electronic medical records of 681,122 patients aged 6–19 years who were enrolled in an integrated health plan 2007–2009. Weight class was assigned based on BMI‐for‐age. Overall, 18.4% of youth had a history of asthma and 10.9% had current asthma. Adjusted odds of current asthma for overweight, moderately obese, and extremely obese youth relative to those of normal weight were 1.22 (95% confidence interval (CI): 1.20, 1.24), 1.37 (95% CI: 1.34, 1.40), and 1.68 (95% CI: 1.64, 1.73), respectively (P trend < 0.001). Black youth are nearly twice as likely (adjusted odds ratio (OR) = 1.93, 95% CI: 1.89, 1.99), and Hispanic youth are 25% less likely (adjusted OR = 0.75, 95% CI: 0.74, 0.77), to have current asthma than to non‐Hispanic white youth. However, the relationship between BMI and asthma was strongest in Hispanic and weakest in black youth. Among youth with asthma, increasing body mass was associated with more frequent ambulatory and emergency department visits, as well as increased inhaled and oral corticosteroid use. In conclusion, overweight, moderate, and extreme obesity are associated with higher odds of asthma in children and adolescents, although the association varies widely with race/ethnicity. Increasing BMI among youth with asthma is associated with higher consumption of corticosteroids and emergency department visits.

Incidence of herpes zoster among children vaccinated with varicella vaccine in a prepaid health care plan in the United States, 2002-2008.

Background: Herpes zoster (HZ), or shingles, is caused by reactivation of latent varicella-zoster virus after a primary infection with either wild-type or vaccine-type varicella-zoster virus, the latter having been introduced in 1995 for children. Since then, few population-based data about the incidence of childhood HZ are available. Methods: We identified children aged ≤12 years who were vaccinated with 1 dose of varicella vaccine between 2002 and 2008 in a prepaid health plan and followed them through their electronic health records for a diagnosis of HZ. The medical records of these children were reviewed. Persistent and chronic conditions for these children before HZ were identified. Results: There were 172,163 children vaccinated, with overall follow-up of 446,027 person-years (Incidence rate = 27.4 per 100,000 person-years, 95% confidence interval: 22.7–32.7). Children vaccinated after age 5 years had a higher but not statistically significant different rate than children vaccinated between 12 and 18 months (34.3 vs. 28.5 per 100,000 person-years). Among children vaccinated between 12 and 18 months, incidence rates gradually increased each year in the first 4 years after vaccination (P < 0.001). Among the HZ cases, there were 1 (0.7%) case of lymphoid leukemia, 1 (0.7%) case of drug abuse, 16 (11.1%) cases of asthma with 3 or more acute exacerbations, 12 (8.3%) cases of developmental disorders, and 3 (2.1%) cases of psychological or mental disorders. Conclusions: These data demonstrate that diagnosed HZ is rare among children following varicella vaccine. Despite the small numbers, the roles of delayed vaccination, severe asthma, and development disorders warrant further investigation. In the future, analyses of HZ isolates will be needed to identify the virus strains causing reactivation.

Herpes Zoster Vaccine and the Incidence of Recurrent Herpes Zoster in an Immunocompetent Elderly Population

BACKGROUND The benefit of vaccinating immunocompetent patients who have had shingles has not been examined. The study assessed the association between vaccination and the incidence of herpes zoster recurrence among persons with a recent episode of clinically diagnosed herpes zoster. METHODS This is a matched cohort study in Kaiser Permanente Southern California. Study populations were immunocompetent elderly individuals ≥ 60 years old with a recent episode of herpes zoster. Incidence of recurrent herpes zoster was compared between the vaccinated and the unvaccinated matched cohorts. RESULTS A total of 1036 vaccinated and 5180 unvaccinated members were included. On the basis of clinically confirmed cases, the incidence of recurrent herpes zoster among persons aged <70 years was 0.99 (95% confidence interval [CI], .02-5.54) and 2.20 (95% CI, 1.10-3.93) cases per 1000 person-years in the vaccinated and unvaccinated cohorts, respectively. The adjusted hazard ratio was 0.39 (95% CI, .05-4.45) among persons aged <70 years and 1.05 (95% CI, .30-3.69) among persons aged ≥ 70 years. CONCLUSIONS The risk of herpes zoster recurrence following a recent initial episode is fairly low among immunocompetent adults, regardless of vaccination status. Such a low risk suggests that one should evaluate the necessity of immediately vaccinating immunocompetent patients who had a recent herpes zoster episode.

Pediatric obesity and gallstone disease.

Objectives: The aim of the present study was to investigate the association between childhood and adolescent obesity, the risk of gallstones, and the potential effect modification by oral contraceptive use in girls. Methods: For this population-based cross-sectional study, measured weight and height, oral contraceptive use, and diagnosis of cholelithiasis or choledocholithiasis were extracted from the electronic medical records of 510,816 patients ages 10 to 19 years enrolled in an integrated health plan, 2007–2009. Results: We identified 766 patients with gallstones. The adjusted odds ratios (95% CI) of gallstones for under-/normal-weight (reference), overweight, moderate obesity, and extreme obesity in boys were 1.00, 1.46 (0.94%–2.27%), 1.83 (1.17%–2.85%), and 3.10 (1.99%–4.83%) and in girls were 1.00, 2.73 (2.18%–3.42%), 5.75 (4.62%–7.17%), and 7.71 (6.13%–9.71%), respectively (P for interaction sex × weight class <0.001). Among girls, oral contraceptive use was associated with higher odds for gallstones (odds ratio 2.00, 95% CI 1.66%–2.40%). Girls who used oral contraceptives were at higher odds for gallstones than their counterparts in the same weight class who did not use oral contraceptives (P for interaction weight class × oral contraceptive use 0.023). Conclusions: Due to the shift toward extreme childhood obesity, especially in minority children, pediatricians can expect to face increasing numbers of children and adolescents affected by gallstone disease.

Phosphorus and risk of renal failure in subjects with normal renal function.

PURPOSE Whether higher serum phosphorus levels increase risk for kidney disease onset and progression to end-stage renal disease in those with normal renal function is largely unknown. We sought to determine whether higher serum phosphorus levels increase risk for end-stage renal disease within a large ethnically diverse population with normal kidney function. METHODS A retrospective longitudinal cohort study was performed in the period January 1, 1998 through December 31, 2008 of adults within a vertically integrated health plan (3.4 million members). The primary objective was to determine risk of incident end-stage renal disease. Baseline and time-averaged phosphorus were used for Cox regressions analyses to calculate hazard ratios (HR) adjusting for age, sex, race, pre-existing hypertension, and diabetes. RESULTS A total of 94,989 subjects were identified in the 11-year observation period. Mean age of the cohort was 50 years, with 61% female, 38% white, 14% black, and 25% Hispanic. Population-based phosphorus quartile ranges were 1.9-3.0 mg/dL, 3.1-3.4 mg/dL, 3.5-3.8 mg/dL, and 3.9-5.7 mg/dL. End-stage renal disease occurred in 130 (0.1%) subjects. Every 0.5-mg/dL phosphorus increase demonstrated an adjusted HR of 1.40 (95% confidence interval [CI], 1.06-1.84) and HR for mortality of 1.09 (95% CI, 1.06-1.13). Adjusted HRs were 0.64 (95% CI, 0.37-1.11), 0.83 (95% CI, 0.50-1.39), and 1.48 (95% CI, 0.96-2.28) in the 2nd, 3rd, and 4th quartile, respectively, compared with the first phosphorus quartile. Time-averaged serum phosphorus demonstrated a similar relationship across quartiles and as a continuous variable. CONCLUSION In our large, ethnically diverse cohort of non kidney disease subjects, higher serum phosphorus levels were associated with greater risk for end-stage renal disease and mortality.

Evaluation of the incidence of herpes zoster after concomitant administration of zoster vaccine and polysaccharide pneumococcal vaccine.

In 2009, a revision to the zoster vaccine package insert was approved stating that the zoster vaccine and the pneumococcal vaccine should not be given concurrently because concomitant use resulted in reduced immunogenicity of the zoster vaccine. We conducted an observational study to evaluate if concomitant vaccination reduces the protective effect of the zoster vaccine. The study was conducted in Kaiser Permanente Southern California. Incidence of herpes zoster (HZ) after vaccination with a zoster vaccine in the population receiving both vaccines on the same day was compared to that in the population receiving a pneumococcal vaccine within one year to 30 days prior to zoster vaccine. Vaccinations and incident HZ cases were identified by electronic health records. The hazard ratio for incident HZ associated with concomitant vs. nonconcomitant vaccination was estimated using the Cox proportional hazard model. There were 56 incident HZ cases in the concomitant vaccination cohort and 58 in the nonconcomitant vaccination cohort, yielding a HZ incidence of 4.54 (95% confidence interval [CI], 3.43-5.89) and 4.51 (95% CI, 3.42-5.83) per 1000 person-years, respectively. The hazard ratio comparing the incidence rate of HZ in the two cohorts was 1.19 (95% CI, 0.81-1.74) in the adjusted analysis. In this study, we found no evidence of an increased risk of HZ in the population receiving zoster vaccine and pneumococcal vaccine concomitantly. The revision of the product information needs to be carefully assessed to avoid introducing barriers to patients and providers who are interested in these two important vaccines.