Biomedical subjects

Tonya S King

Publications and source records attributed to Tonya S King.

7 recordsLinked to original sources

PubMed2007

A repeated measures concordance correlation coefficient.

The concordance correlation coefficient is commonly used to assess agreement between two raters or two methods of measuring a response when the data are measured on a continuous scale. However, the situation may arise in which repeated measurements are taken for each rater or method, e.g. longitudinal studies in clinical trials or bioassay data with subsamples. This paper proposes a coefficient for measuring agreement between two raters or two methods of measuring a response in the presence of repeated measurements. We illustrate the methodology with examples comparing (1) 1-hr versus 2-hr blood draws for measuring cortisol in an asthma clinical trial and (2) two measurements of percentage body fat, from skinfold calipers and dual energy X-ray absorptiometry.

Absorptiometry, Photon↗

PubMed2007

The Predicting Response to Inhaled Corticosteroid Efficacy (PRICE) trial.

BACKGROUND: Although guidelines recommend anti-inflammatory therapy for persistent asthma, recent studies suggest that 25% to 35% of patients with asthma may not improve lung function with inhaled corticosteroids. OBJECTIVE: To evaluate potential biomarkers of predicting short-term (6-week) response to inhaled corticosteroid with subsequent evaluation of responders and nonresponders to asthma control over a longer interval (16 additional weeks). METHODS: Eighty-three subjects with asthma off steroid were enrolled in this multicenter study. Biomarkers and asthma characteristics were evaluated as predictors of inhaled corticosteroid response over a 6-week trial for changes in FEV(1) and methacholine PC(20). After this, an additional 4-month trial evaluated asthma control. RESULTS: Although multiple baseline predictors had significant correlations with improvements for short-term inhaled steroid success, the only strong correlations (r >or= +/- 0.6) were albuterol reversibility (r = 0.83; P < .001), FEV(1)/forced vital capacity (r = -0.75; P < .001), and FEV(1) % predicted (r = -0.71; P < .001). Dividing the subjects in the short-term inhaled steroid trial into responders (>5% FEV(1) improvement) and nonresponders (<or=5%) determined the longer-term need for steroids. For the nonresponders, asthma control remained unchanged whether inhaled corticosteroids were continued or were substituted with a placebo (P = .99). The good short-term responders maintained asthma control longer-term only if maintained on inhaled steroids (P = .007). CONCLUSION: The short-term response to inhaled corticosteroids with regard to FEV(1) improvement predicts long-term asthma control. CLINICAL IMPLICATIONS: The decision to use long-term inhaled steroids could be based on a short-term trial. Different therapeutic strategies would need to be established for nonresponders.

Adult↗

PubMed2005

Daily versus as-needed corticosteroids for mild persistent asthma.

BACKGROUND: Although guidelines recommend daily therapy for patients with mild persistent asthma, prescription patterns suggest that most such patients use these so-called controller therapies intermittently. In patients with mild persistent asthma, we evaluated the efficacy of intermittent short-course corticosteroid treatment guided by a symptom-based action plan alone or in addition to daily treatment with either inhaled budesonide or oral zafirlukast over a one-year period. METHODS: In a double-blind trial, 225 adults underwent randomization. The primary outcome was morning peak expiratory flow (PEF). Other outcomes included the forced expiratory volume in one second (FEV1) before and after bronchodilator treatment, the frequency of exacerbations, the degree of asthma control, the number of symptom-free days, and the quality of life. RESULTS: The three treatments produced similar increases in morning PEF (7.1 to 8.3 percent; approximately 32 liters per minute; P=0.90) and similar rates of asthma exacerbations (P=0.24), even though the intermittent-treatment group took budesonide, on average, for only 0.5 week of the year. As compared with intermittent therapy or daily zafirlukast therapy, daily budesonide therapy produced greater improvements in pre-bronchodilator FEV1 (P=0.005), bronchial reactivity (P<0.001), the percentage of eosinophils in sputum (P=0.007), exhaled nitric oxide levels (P=0.006), scores for asthma control (P<0.001), and the number of symptom-free days (P=0.03), but not in post-bronchodilator FEV1 (P=0.29) or in the quality of life (P=0.18). Daily zafirlukast therapy did not differ significantly from intermittent treatment in any outcome measured. CONCLUSIONS: It may be possible to treat mild persistent asthma with short, intermittent courses of inhaled or oral corticosteroids taken when symptoms worsen. Further studies are required to determine whether this novel approach to treatment should be recommended.

Administration, Inhalation↗

PubMed2004

Prospective validation of a perinatal bacterial vaginosis screening risk score.

OBJECTIVE: Prospectively validate an antenatal bacterial vaginosis (BV) risk score at two public health department obstetrics clinics. STUDY DESIGN: Women (n=409) entering prenatal care received a BV risk score (range 0 to 16) at their first visit and at 24 to 28 weeks' gestation. BV was measured with Gram-stained vaginal smears. Normal discharge was used as a surrogate for being asymptomatic. RESULTS: Approximately half of the women scored > or =3 at each assessment. In total 29% had true BV at the first assessment (13% at the second assessment). The BV risk score (> or =3) had 91% sensitivity and 63% specificity, and the BV risk score (> or =5) had 88% sensitivity and 76% specificity. Among true cases, 42% were asymptomatic, of which 77% had risk scores > or =3. All symptomatic BV cases had risk scores > or =3. CONCLUSION: In practice, the risk score identified both asymptomatic and symptomatic cases. Asymptomatic women are of particular interest because they are not screened for BV under current practice guidelines.

Adolescent↗

PubMed2004

Outcomes of states' scholarship, loan repayment, and related programs for physicians.

CONTEXT: Many states attempt to entice young generalist physicians into rural and medically underserved areas with financial support-for-service programs-scholarships, service-option loans, loan repayment, direct financial incentives, and resident support programs-with little documentation of their effectiveness. OBJECTIVE: The objective of this study was to assess outcomes of states' support-for-service programs as a group and to compare outcomes of the 5 program types. DESIGN: We conducted a cross-sectional, primarily descriptive study. PARTICIPANTS: We studied all 69 state programs operating in 1996 that provided financial support to medical students, residents, and practicing physicians in exchange for a period of service in underserved areas; federally funded initiatives were excluded. We also surveyed 434 generalist physicians who served in 29 of these state programs and a matched comparison group of 723 nonobligated young generalist physicians. DATA COLLECTION: Information on eligible programs was collected by telephone, mail questionnaires, and from secondary sources. Obligated and nonobligated physicians were surveyed, with 80.3% and 72.8% response rates, respectively. MAIN OUTCOME MEASURES: Levels of socioeconomic need of communities and patients served by physicians, programs' participant service completion and retention rates, and physicians' satisfaction levels. RESULTS: Compared with young nonobligated generalists, physicians serving obligations to state programs practiced in demonstrably needier areas and cared for more patients insured under Medicaid and uninsured (48.5% vs. 28.5%, P <0.001). Service completion rates were uniformly high for loan repayment, direct incentive, and resident-support programs (93% combined) but lower for student-targeting service-option loan (mean, 44.7%) and scholarship (mean, 66.5%) programs. State-obligated physicians were more satisfied than nonobligated physicians, and 9 of 10 indicated that they would enroll in their programs again. Obligated physicians also remained longer in their practices than nonobligated physicians (P = 0.03), with respective group retention rates of 71% versus 61% at 4 years and 55% versus 52% at 8 years. Retention rates were highest for loan repayment, direct incentive, and loan programs. CONCLUSIONS: States' support-for-service programs bring physicians to needy communities where a strong majority work happily and with at-risk patient populations; half stay over 8 years. Loan repayment and direct financial incentive programs demonstrate the broadest successes.

Adult↗

PubMed2002

Influence of a family program on adolescent smoking and drinking prevalence.

Reducing the prevalence of adolescent cigarette smoking and alcohol drinking are public health goals of the United States. Although families have strong influence on their children, few randomized studies have examined whether family-directed programs influence those behaviors in general universal populations. This paper reports findings from an evaluation of a family program that features the mailing of four booklets to adult family members with follow-up telephone calls by health educators. A national sample of adolescent-parent pairs and a randomized experimental design were used to evaluate the program. Baseline users and nonusers of those substances were considered simultaneously in analyses so that program influences on smoking and drinking prevalence could be examined. The findings suggest that the program significantly reduced the prevalence of smoking cigarettes and drinking alcohol among adolescents. These findings are discussed in the context of earlier reports of research on the family program and implications for public health.

Adolescent↗

PubMed2002

Prospective clinical trial of dental implants in persons with ectodermal dysplasia.

STATEMENT OF PROBLEMS: Ectodermal dysplasia is a hereditary condition in which hypodontia is the second most frequently occurring sign. Hypodontia is associated with lack of development of the alveolar ridge and results in less volume of bone for support of conventional prostheses. Minimal development of the alveolar ridge can affect the bone volume available for the placement of dental implants. PURPOSE: This clinical trial evaluated the survival of implants placed in individuals with a form of ectodermal dysplasia and severe hypodontia. MATERIAL AND METHODS: Two hundred sixty-four titanium endosteal dental implants were placed in 51 subjects: 37 males and 14 females between the ages of 8 and 68 (mean age 20.5 years, median age 16.5 years). Two hundred forty-three implants were placed in the anterior mandible, and 21 were placed in the anterior maxilla with a 2-stage surgical protocol. Either fixed-detachable dentures or bar-clip overdentures were provided. Subjects were followed up for 0 to 78 months after second-stage surgery. Kaplan-Meier survival rates and curves were produced to describe the survival of the implants for the different age groups and implant locations. Repeated-measures Cox regression models were used to evaluate the hazard ratios for age and location, with alpha=.05 as the criteria for significance. RESULTS: Of the 243 implants placed in the anterior mandible, 221 (91%) survived. Of the 21 implants placed in the anterior maxilla, 16 (76%) survived. Fourteen of the 51 (27%) subjects had a failed implant. All but 2 failures occurred before or at second-stage surgery. Implant-supported prostheses were provided for all patients. CONCLUSION: Within the limitations of this study, the results support the continued use of endosteal dental implants in this patient population with appropriate precautions in the maxilla.

Adolescent↗