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Biomedical subjects

G G Koch

Publications and source records attributed to G G Koch.

At least 55 records · Page 3Linked to original sources
PubMed1997

The relationship between clinical tooth status and receipt of sealants among child Medicaid recipients.

This study investigated the association between caries status and sealant need at a prior survey and subsequent sealant use in a Medicaid program. Clinical data from a 1986-87 statewide epidemiological survey (N = 8026) representative of North Carolina (NC) schoolchildren (grades K-12) were linked with all NC Medicaid dental claims submitted during 1987-92, yielding 570 children in the survey who had at least one dental visit during 1987-1992. From the 570, 390 children were included: 71 who received sealants (S) and 319 who received non-sealant care (NS). Children were excluded based on age, having preexisting sealants, or having no sealant-eligible molars or premolars. S and NS were compared on baseline dfs, DMFS, and sealant need, controlling for the patient's age, number of visits, and the provider's propensity to seal. At all ages, NS was twice as likely to have had prior dfs or DMFS (OR = 2.04, 95% CI = 1.15, 3.70). The association between sealant receipt and prior sealant need varied by age. At 6 to 11 years, S and NS had equal likelihood of sealant need (OR = 1.41, 95% CI = 0.62, 3.18). At 12 to 15 years, NS had a greater likelihood of sealant need (OR = 6.82, 95% CI = 1.60, 29.08). Caries-free status was associated with subsequent sealant receipt. Prior sealant need caused variability in dentists' decisions, depending on the child's age and past caries experience. Sealants were used infrequently by most providers and for a minority of patients. These findings are important for the Medicaid program and for future non-randomized studies of sealant effectiveness.

Adolescent↗
PubMed1997

Secondary sexual characteristics and menses in young girls seen in office practice: a study from the Pediatric Research in Office Settings network.

OBJECTIVE: To determine the current prevalence and mean ages of onset of pubertal characteristics in young girls seen in pediatric practices in the United States. METHODS: A cross-sectional study was conducted by 225 clinicians in pediatric practices belonging to Pediatric Research in Office Settings, a practice-based research network. After standardized training in the assessment of pubertal maturation, practitioners rated the level of sexual maturation on girls 3 through 12 years who were undergoing complete physical examinations. RESULTS: Data were analyzed for 17,077 girls, of whom 9.6% were African-American and 90.4% white. At age 3, 3% of African-American girls and 1% of white girls showed breast and/or pubic hair development, with proportions increasing to 27.2% and 6.7%, respectively, at 7 years of age. At age 8, 48.3% of African-American girls and 14.7% of white girls had begun development. At every age for each characteristic, African-American girls were more advanced than white girls. The mean ages of onset of breast development for African-American and white girls were 8.87 years (SD, 1.93) and 9.96 years (SD, 1.82), respectively; and for pubic hair development, 8.78 years (SD, 2.00) and 10.51 years (SD, 1.67), respectively. Menses occurred at 12.16 years (SD, 1.21) in African-American girls and 12.88 years (SD, 1.20) of age in white girls. CONCLUSIONS: These data suggest that girls seen in a sample of pediatric practices from across the United States are developing pubertal characteristics at younger ages than currently used norms. Practitioners may need to revise their criteria for referral of girls with precocious puberty, with attention to racial differences.

Age Distribution↗
PubMed1997

Design principles and statistical considerations in periodontal clinical trials.

Although clinical trials are a small subset of conducted biomedical research, they have become powerful investigational tools for the evaluation and approval of new treatments by clinician groups and regulatory agencies like the US Food and Drug Administration. To impact the delivery of care, trials in general must meet three criteria: clarity, comparability, and generalizability. Accordingly, trials can offer meaningful data if they have procedures which are well defined and subjects who represent a reasonably homogeneous population. The evaluation of periodontitis interventions presents several challenges due to the disease's heterogeneity and its irregular, episodic pattern; nevertheless, the intent of these novel interventions is to prevent, diagnose, inhibit, or reverse periodontal disease progression. Careful consideration of the trial's objectives should dictate clinical endpoints (primary and surrogate), comparison groups (placebo, standard therapy, test therapy), and equivalence versus superiority as the basis for conclusions. Several design elements such as control population specification, randomization, masking, sample size calculation, and standardization of procedures for patient care and assessment can decrease potential bias and variability. In both parallel and paired (split-mouth) design trials, multiplicities of endpoints, treatments, and subgroups require strategies which address the broader scope of chance findings without excessive loss of study power. Also, the longitudinal assessment of multiple periodontal sites within patients produces correlated data structures for which analytic methods need to account for the appropriate sampling unit. With these design and analytic elements, clinical trials can provide important evidence to investigators, patients, and governmental agencies for the introduction of novel interventions in periodontal practice.

Clinical Trials as Topic↗
PubMed1997

Comparison of manual and automated probing in an untreated periodontitis population.

Diagnosis of periodontal disease progression involves recording two probing attachment level measurements over an adequate time interval. A diagnostic instrument which exhibits less measurement variability allows for increased sensitivity and earlier disease detection. Traditionally, a manual probe with an occlusal stent of the cementoenamel junction (CEJ) as a reference landmark has been the method of choice. Automated probes that use an occlusal disk as the reference landmark have been developed as an alternative means of measure. The aim of this study was to compare the variability of these two probing methods. Four hundred eleven (411) interproximal sites in 46 untreated periodontitis patients were monitored by a single examiner over a 6-month period. Each site was measured on a monthly basis, first with an automated probe (AP) followed by a manual probe (MP) in combination with a custom-fabricated acrylic stent. Measurement variability of the two probing methods was also compared over a 7-day interval. The AP measurements were significantly more variable than the MP measurements (P < 0.001) when considering the variability between two passes at the same visit. Over the 6-month period, the MP measurements demonstrated significantly more variability than the AP measurements (P < 0.001). It was also noted that MP measurements exhibited more variability at sites with frequent bleeding during the 6 months of the study (P = 0.006). The results of this study demonstrate that AP may have less variability of attachment level measurements over a 6-month period and may be less influenced by local inflammatory changes. However, future comparison studies should include multiple examiners to reduce examiner bias and should alternate the probing method to reduce bias created by local tissue changes from multiple probings.

Adult↗
PubMed1996

The awareness-to-adherence model of the steps to clinical guideline compliance. The case of pediatric vaccine recommendations.

OBJECTIVES: This article proposes, tests, and explores the potential applications of a model of the cognitive and behavioral steps physicians take when they comply with national clinical practice guidelines. The authors propose that when physicians comply with practice guidelines, they must first become aware of the guidelines, then intellectually agree with them, then decide to adopt them in the care they provide, then regularly adhere to them at appropriate times. METHODS: Data used to test this model address physicians' responses to national pediatric vaccine recommendations. Questionnaires were mailed to 3,014 family physicians and pediatricians who were working in communities of various sizes in nine states. RESULTS: The survey response rate was 66.2%. In the case of the recommendation to provide hepatitis B vaccine to all infants, guideline awareness among respondents was 98.4%, agreement 70.4%, adoption 77.7%, and adherence 30.1%. The data for 87.9% of physicians fit the model at every step. Significant deviation from the model occurred only for the 11% of all physicians who adopted the hepatitis B recommendation without agreeing with it. In the case of the recommendation to provide the acellular variety of the pertussis vaccine for children's fourth and fifth pertussis doses, guideline awareness among respondents was 89.8%, agreement 66.5%, adoption 46.3%, and adherence 35.2%. Data fit the model at every step for 90.6% of physicians. Greater likelihood of movement from each step to the next in the path to adherence was found for physicians with certain characteristics, information sources, and beliefs about the vaccines, and those in certain types of practice settings. Specific physician and practice characteristics typically predicted movement along only one or two of the steps to adherence to either the hepatitis B or acellular pertussis recommendations. CONCLUSIONS: These data on physicians' use of pediatric vaccine recommendations generally support the awareness-to-adherence model. This model may prove useful in identifying ways to improve physicians' adherence to a variety of guidelines by demonstrating where physicians fall off the path to adherence, which physicians are at greatest risk for not attaining each step in the path, and factors associated with a greater likelihood of attaining each step toward guideline adherence.

Awareness↗
PubMed1996

Adjustment of the M-component of the DMFS index for prevalence studies of older adults.

Cross-sectional studies of caries in older adults report a substantial number of missing teeth, making it difficult to estimate caries experience accurately. The goal of this study was to improve the method of estimating caries experience as expressed by the DMFS index in population groups with missing teeth. The adjustment was demonstrated with reference to the Piedmont 65+ Dental Study conducted on a random sample of 363 community-dwelling older adults in North Carolina who were followed for 5 years. These older dentate adults had a mean (+/-SE) of 11.7 +/- 0.5 teeth missing at baseline, 56.1 +/- 2.5 missing surfaces and a DMFS of 86.7 +/- 2.0. A predicted caries prevalence was determined from the DFS at 5 yrs plus the 5-yr DFS incidence and the baseline DFS of teeth lost during the study period. Then a formula was developed that would estimate the predicted caries prevalence as a function of the observed 5-yr DMFS. This formula provided a good estimation of caries prevalence at 5 yrs (DMFSadj) when compared with the predicted prevalence (paired t-test, p > 0.05), while prevalence was underestimated by the DFS and greatly overestimated by the traditional DMFS index. Subgroup analyses by race, sex, and periodontal status also indicated that the DMFSadj resulted in patterns of estimates similar to the predicted prevalence, while the DFS and the DMFS were likely to result in different findings. The DMFS from the time of tooth eruption also was adjusted using this formula. The resulting analyses of subgroup differences in caries were not different from the previous estimates based on the 5-yr historical data, indicating that the adjustment of all M surfaces avoids the biases inherent in the traditional DMFS and DFS indices. This study showed that predicted caries prevalence could be estimated by adjusting the M component of the DMFS. It appears that this adjustment formula can be used without obvious bias, but additional studies are needed to provide adjustment figures for populations with different caries prevalences.

Black or African American↗
PubMed1996

Innovative strategies using SUDAAN for analysis of health surveys with complex samples.

Large-scale health surveys provide a wealth of information for addressing problems in health sciences research. Designed for multiple purposes, these surveys frequently have large sample sizes and extensive measurements of demographic and socioeconomic characteristics, risk factors, disease outcomes and health care service use and costs. Complex features of the sampling design typically employed to select the survey sample, coupled with the vast amount of information available from the survey database, underlie issues that must be addressed during data processing and analysis. Numerous articles in the literature have focused on the debate of whether or not, and how, to control for features of the sample design during data analysis. Traditional statistical methods for simple random samples and the software that accompanies them have historically not had the capacity to account for the survey design. Recent advancements in statistical methodology for survey data analysis have greatly expanded the analytical tools available to the survey analyst. Commercial software packages that incorporate these methods offer the analyst convenient ways for applying such tools to large survey databases in an easy and efficient manner. We present an overview of analysis strategies for survey data and illustrate their application via the SUDAAN software system. Examples for analyses are provided through data from two large US health surveys, the National Health Interview Survey and the Longitudinal Study of Aging. Questions of both a cross-sectional and longitudinal nature are addressed. The examples involve logistic regression, time-to-event analysis, and repeated measures analysis.

Aged↗
PubMed1996

Exploratory case-control analysis of psychosocial factors and adult periodontitis.

We explored the association between social factors and adult periodontitis by comparing self-reported information for daily strains and symptoms of depression in 71 cases and 77 controls. Cases and controls were selected from among 1,426 participants in the Erie County Risk Factor Study. We found differences among those who scored higher than their peers on measures of social strain. The odds ratio (OR) and 95% confidence interval (95% CI) for the association between case status and Role Strain score of 2.27 or more was 2.84, 95% CI = 1.08 to 7.46. We also examined serum antibody, dichotomized at the median, for three periodontal pathogens (Bacteroides forsythus [IgG Bf], Porphyromonas gingivalis [IgG Pg], Actinobacillus actinomycetemcomitans [IgG Aa]), and assessed interaction between antibody levels and a Depression score derived from the Brief Symptom Inventory. IgG Pg and IgG Aa were both strongly associated with case status (OR = 4.52, 95% CI = 1.99 to 10.3 and OR = 5.29, 95% CI = 2.34 to 12.0, respectively). IgG Bf was associated with periodontal disease but only among individuals who had higher scores for Depression (OR = 6.75, 95% CI = 1.25 to 36.5). Smoking status was associated with case status (OR = 4.95, 95% CI = 1.86 to 13.2). We assessed these findings prospectively by examining factors associated with more extensive disease among the 71 case subjects after 1 year of follow-up. We found baseline smoking status and IgG Bf among individuals scoring high on Depression at baseline to be associated with more extensive disease (8.1% or more of the sites showing further breakdown). In this population an elevated Depression score may be a marker for social isolation, which could play a role in immune function during periods of social strain. This exploratory analysis has served to identify specific lines of inquiry concerning psychosocial measures as important environmental factors in adult periodontitis.

Adult↗
PubMed1996

Risk indicators for hospitalization during the last year of life.

OBJECTIVE: High levels of hospital expenditures for older people during their last year of life are widely documented. However, evidence of the association between prospectively measured indicators and subsequent hospitalization is sparse. This article investigates the pattern of hospitalization for a sample of Medicare enrollees during their last year of life. DATA SOURCES: Data from the Longitudinal Study of Aging, a national study of persons age 70 and older, are used. Only data on decedents are used. STUDY DESIGN: We determine individual characteristics (including functional status, evidence of disease, living arrangement, and prior hospitalization) shortly before the last year of life. A distinction is made between terminal and nonterminal admissions. National estimates and regression analyses using survey weights are conducted. PRINCIPAL FINDINGS: The likelihood of any use is high regardless of age, functional status, or the presence of major diseases. Although only a few indicators are associated with having a terminal stay, a number of indicators are associated with nonterminal use. Nonterminal stays and total nights hospitalized are positively associated with prior evidence of disease, prior hospitalization, and age, although the probability of nonterminal use decreases with age for persons over 82 years old. The relationship between use and functional status depends on whether persons lived alone, were institutionalized, or had private health insurance. CONCLUSIONS: This study demonstrates that while it is difficult to predict who will be admitted to the hospital at the time of death, a number of characteristics existing before the last year of life are associated with nonterminal hospitalization and total nights hospitalized during the last year of life.

Age Factors↗
PubMed1995

Function of von Willebrand factor after crossed bone marrow transplantation between normal and von Willebrand disease pigs: effect on arterial thrombosis in chimeras.

von Willebrand factor (vWF) is essential for the induction of occlusive thrombosis in stenosed and injured pig arteries and for normal hemostasis. To separate the relative contribution of plasma and platelet vWF to arterial thrombosis, we produced chimeric normal and von Willebrand disease pigs by crossed bone marrow transplantation; von Willebrand disease (vWD) pigs were engrafted with normal pig bone marrow and normal pigs were engrafted with vWD bone marrow. Thrombosis developed in the chimeric normal pigs that showed normal levels of plasma vWF and an absence of platelet vWF; but no thrombosis occurred in the chimeric vWD pigs that demonstrated normal platelet vWF and an absence of plasma vWF. The ear bleeding times of the chimeric pigs were partially corrected by endogenous plasma vWF but not by platelet vWF. Our animal model demonstrated that vWF in the plasma compartment is essential for the development of arterial thrombosis and that it also contributes to the maintenance of bleeding time and hemostasis.

Animals↗
PubMed1995

Exaggerated atrial repolarization waves as a predictor of false positive exercise tests in an unselected population.

The authors previously postulated that a markedly downsloping PR-segment might be a marker for exaggerated atrial repolarization waves and demonstrated PR-segment appearance to be an independent predictor of a false positive exercise test. This study was conducted to determine the sensitivity, specificity, and predictive value of markedly downsloping PR-segments for predicting false positive exercise tests. The study group consisted of 82 consecutive patients with a positive exercise test (> or = 1.0 mm horizontal ST depression) and a normal resting electrocardiogram. Tests were predicted to be false positive based on previously defined criteria: (1) markedly downsloping PR-segments in two or more of leads II, III, and aVF and (2) exercise duration 4 minutes or longer. Patients were then classified according to available clinical information (coronary angiography and radionuclide stress testing) into true positive (due to myocardial ischemia, n = 62) and false positive (n = 20) groups. The sensitivity, specificity, and predictive value of the PR-segment/exercise duration criterion for predicting a false positive test were 70, 74, and 47%, respectively. Patients with false positive tests also had higher heart rates (158 +/- 16 vs 136 +/- 20 beats/min, P < .001) and less frequent chest pain (15 vs 46%, P = .017) during the exercise test. Patients with false positive exercise tests can be recognized by the achievement of a high peak exercise heart rate, the absence of exercise-induced chest pain, and the appearance of markedly downsloping PR-segments in the inferior leads.

Atrial Function↗
PubMed1995

Validation of the Minimum Data Set Cognitive Performance Scale: agreement with the Mini-Mental State Examination.

BACKGROUND: Almost all nursing homes in the United States are required by the 1987 Omnibus Budget Reconciliation Act to assess each resident's functional, medical, psychosocial, and cognitive status using a standard instrument known as the Minimum Data Set (MDS). We report a validation study to show that the MDS Cognitive Performance Scale (CPS), a cognitive measure generated from 5 MDS items (comatose status, decision making, short-term memory, making self understood, and eating) can be used to detect cognitive impairment as defined by the Mini-Mental State Examination (MMSE). METHODS: Two hundred subjects were randomly recruited from 8 nursing home facilities in North Carolina. Two medical students administered the MMSE, while a geriatric research nurse was responsible for collecting MDS cognitive items, which included the 5 items required for generating CPS scores. Cognitive impairment was defined by MMSE scores adjusted for education. Agreement between the CPS and the MMSE in identifying cognitively impaired subjects was then evaluated. RESULTS: The CPS showed substantial agreement with the MMSE in the identification of cognitive impairment; the sensitivity was .94 (95% confidence interval [CI]: .90, .98), the specificity was .94 (95% CI: .87, .96), and the diagnostic accuracy as measured by the area under the receiver operating characteristics (ROC) curve was .96 (95% CI: .88, 1.0). CONCLUSIONS: The MDS Cognitive Performance Scale, when performed by a trained research nurse using recommended protocols, provides a valid measure of cognitive status in nursing home residents.

Aged↗
PubMed1995

Self-care and assistance from others in coping with functional status limitations among a national sample of older adults.

Using data from the first wave of a new longitudinal data set collected in the late fall and winter of 1990-1991, the National Survey of Self-Care and Aging (NSSCA), we examined older adults' self-care practices in coping with functional status limitations based on in-person interviews with a national probability sample of 3,485 noninstitutionalized adults aged 65 or older selected from Medicare beneficiary files. A composite score of functional status was calculated to reflect the presence and severity of disability in three dimensions: basic, mobility, and instrumental activities of daily living. Three types of self-care coping strategies were defined: use of equipment or devices, changes in behavior, and modifications in one's environment. National estimates of self-care practices, assistance from others, and functional status measures were presented. Data revealed that the likelihood of engaging in self-care coping strategies increased as the severity of disability increased, except among the most severely disabled. Generally, those receiving assistance from others were more likely to engage in self-care activities, suggesting that receiving assistance supplements, rather than supplants, self-care coping strategies.

Activities of Daily Living↗
PubMed1995

Validation of a screening survey to assess local public health performance.

The study seeks to validate an abbreviated protocol for measuring local public health performance. Primary data were collected during 1993 on a series of indicators keyed to defined public health core functions and their associated practices. The data were obtained from responses provided by local health department directors and were reviewed for accuracy by respective state health department personnel. All local public health jurisdictions (370) in six states were surveyed with a screening protocol. A sample of 36 of these jurisdictions was then resurveyed by means of a full-length protocol using 84 different indicators of public health performance. Correlations between scores obtained from the screening survey and those from the reference survey were high for overall public health performance, for each of the three functions, and for some of the ten practices. A group of only four queries was shown to predict reliably the overall scores. Findings support the conclusion that public health practice can be defined, measured, and monitored. A proposed surveillance system is feasible.

Analysis of Variance↗
PubMed1995

A method for adjusting caries increments for reversals due to examiner misclassification.

Two types of reversals occur in longitudinal caries studies, remineralization (true reversals) and reversals due to examiner misclassification (D3 to S; F to S). Since 1966, the standard practice has been to subtract examiner reversals from the crude increment (CCI), resulting in a net caries increment (NCI). The use of the NCI has been based on the assumption that examiners make an equal number of false positive and false negative errors both at baseline and follow-up examination. Consequently, the difference between the two caries prevalence scores would provide an unbiased estimate of caries incidence between examinations. The NCI considers all reversals to be true reversals which is an extreme strategy, particulary when the level of diagnosis is set at lower thresholds. In this study we compromised between the NCI and CCI by creating a simple formula to calculate the caries increment using a prevalence-based adjustment for reversals. The formula is ADJCI = y2(1-(y3/(y3 + y4))), where y2 = S to D or F; y3 = D or F to S; y4 = D to D/F or F to F. The impact of this adjustment is illustrated using data from a random sample of 452 older black and white adults followed over a 3-yr period. The ADJCI was more likely to result in higher caries increments and more observed intergroup differences than the NCI, a finding that has implications for clinical trials. For example, the crude 3-yr coronal DS increment for whites was 0.62, the NCI was 0.26 and the ADJCI was 0.56. There were significant black-white differences for the CCI and ADJCI, but not the NCI. We conclude that the NCI was too severe of an adjustment for reversals for this study population.

Adult↗
PubMed1995

Three-year tooth loss among black and white older adults in North Carolina.

The distribution and determinants of tooth loss in older adults are poorly defined, especially in Blacks, who have been underrepresented in previous studies. This study investigated, epidemiologically, the distribution and predictors of tooth loss in elder Blacks and Whites by following a random sample of older adults in North Carolina for three years. It was hypothesized that Blacks would be at greater risk of tooth loss and would have different risk factors for tooth loss. Data from 263 Blacks and 228 Whites were collected by dental examinations and interviews conducted in the participants' homes. During the three-year follow-up, 53% of Blacks and 29% of Whites lost at least one tooth. Blacks lost 13% of their remaining teeth compared with 4% for Whites. Logistic regression models showed that factors related to tooth loss for Blacks were: more S. mutans in stimulated saliva, deeper periodontal pockets, more P. intermedia in subgingival plaque, high blood pressure, limited help from others, and few symptoms of depression. For Whites, significant factors were: more lactobacilli in stimulated saliva, history of current oral pain at baseline, more alcohol consumption, no history of past use of calcium or xerostomic medications, higher income, lower occupational prestige, and increased numbers of negative life events. This study showed that older Blacks were at greater risk of tooth loss than older Whites. For both races, factors such as oral bacteria, periodontal conditions, oral symptoms, and psychosocial and economic factors are related to increased risk of tooth loss.

Black or African American↗