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PubMed2005

Analyzing reliability of change in depression among persons with rheumatoid arthritis.

OBJECTIVE: To examine several methods of determining reliability of change constructs in depressive symptoms in patients with rheumatoid arthritis (RA) and to demonstrate the strengths, weaknesses, and uses of each method. METHODS: Data were analyzed from a cohort of 54 persons with RA who participated in a combined behavioral/pharmacologic intervention of 15 months duration. These longitudinal data were used to examine 3 methodologies for assessing the reliability of change for various measures of depression. The specific methodologies involved the calculations of reliable change, sensitivity to change, and reliability of the change score. RESULTS: The analyses demonstrated differences in reliability of change performance across the various depression measures, which suggest that no single measure of depression for persons with RA should be considered superior in all contexts. CONCLUSION: The findings highlight the value of utilizing reliability of change constructs when examining changes in depressive symptoms over time.

Arthritis, Rheumatoid↗

PubMed2003

Biomarkers of aging in women and the rate of longitudinal changes.

The purposes of this study were (1) to estimate biological age score (BAS) in Japanese healthy women based on the 4-7 years longitudinal data for physiological, hematological and biochemical examinations and (2) to examine the rate of aging changes in adult women based on the estimated BAS. The samples consisted of cross-sectional (n=981) and longitudinal (n=110) groups. Out of 31 variables examined, five variables (forced expiratory volume in 1.0 s, systolic blood pressure, mean corpuscular hemoglobin, glucose, albumin/globulin ratio) that met the following criteria: 1) significant cross-sectional correlation with age; 2) significant longitudinal change in the same direction as the cross-sectional correlation; and (3) assessment of redundancy, were selected as candidate biomarkers of aging. This variable set was then submitted into a principal component analysis, and the first principal component obtained from this analysis was used as an equation for assessing one's BAS. Individual BAS showed a high longitudinal stability of age-related changes, suggesting high predictive validity of our newly developed aging measurement equation. However, changes in the aging rate based on the estimated BAS were not constant. The mean slopes of the regression lines of BAS for the three age groups (age<45, 45</=age<65 yrs, 65</=age) were 0.095, 0.065, 0.138, respectively. One-way analysis of variance detected a significant difference (F=5.14, p<0.01) among the three age groups. These results suggest that the rate of aging in adult women is relatively slower until 65 years of age, but after 65, the rate of aging shows a rapid increase. We concluded that the longitudinal method used for selection of variables to compute the BAS was useful and theoretically valid compared to those obtained from cross-sectional data analysis.

Adaptation, Physiological↗

PubMed1994

Longitudinal, expert, all data procedure for psychiatric diagnosis in patients with psychoactive substance use disorders.

The Longitudinal, Expert, All Data (LEAD) procedure has been proposed as a criterion for the assessment of the procedural validity of diagnostic instruments. The authors evaluated the procedure's test-retest reliability and whether it enhanced diagnosis based on a single interview. Data were collected using interviews and questionnaires to assess current and lifetime substance use disorders and common comorbid disorders in 100 patients recruited from a substance abuse treatment program. An initial diagnostic interview was conducted by a primary expert who, at the end of treatment, formulated LEAD diagnoses for each patient, based on the results of the research assessment and all available clinical records. Secondary experts used a similar procedure in a subsample of 40 patients to provide a measure of test-retest reliability. Overall reliability of LEAD diagnoses was good, though it varied from excellent for substance use disorders to poor for some comorbid psychiatric disorders. As a consequence of the LEAD procedure, the total number of substance use diagnoses increased significantly, with no effect on diagnostic reliability. Based on these findings, we conclude that, while the overall reliability of the LEAD procedure is comparable to other diagnostic methods, there was considerable variability among groups of diagnoses. The additional cost of the procedure would appear to be justified only when diagnostic sensitivity is at a premium and principally for the diagnosis of psychoactive substance use disorders. Before it is widely used as a diagnostic criterion measure, the utility of the LEAD procedure should be evaluated in a variety of patient samples and under varying circumstances.

Adult↗

PubMed1997

Lung function and clinical outcome in postpolio patients: a prospective cohort study during 11 years.

The object of this investigation was to prospectively study the annual decline in lung function in a cohort of postpolio patients, and to determine the usefulness of initial lung function tests in the prediction of a subsequent poor outcome. Cross-sectional data were analysed in 55 patients from the total cohort of 350 survivors of poliomyelitis in our admission area of 550,000 inhabitants. Longitudinal data (> 5 yrs, average 8.9 yrs) were available for 31 patients. Seventeen of the patients had a poor outcome (13 were started on domiciliary artificial ventilation and five died from respiratory failure; with one overlap). At the time of entry to the study (on average 4.3 years before the poor outcome), these patients had a lower vital capacity (VC) (43 vs 65% of predicted; p < 0.01) and arterial oxygen tension (Pa,O2) (9.9 vs 11 kPa; p < 0.05) and a higher arterial carbon dioxide tension (Pa,CO2) (6.0 vs 5.0 kPa; p < 0.01). They also had a more rapid increase in Pa,CO2 (0.3 vs 0.03 kPa.yr-1; p < 0.01), but the difference in decline in VC (40 vs 30 mL.yr-1) was not significant. Initial VC < 50% of predicted and/or Pa,CO2 > 6 kPa was associated with a poor prognosis. In conclusion, annual decline in vital capacity was not abnormally rapid but annual increase in arterial carbon dioxide tension was higher in patients with a poor outcome. Initial determination of vital capacity and initial and repeated blood gas analysis appear to be useful in identifying high-risk postpolio patients.

Carbon Dioxide↗

PubMed2000

X-linked congenital adrenal hypoplasia: new mutations and long-term follow-up in three patients.

Mutations of the DAX-1 gene, which encodes a newly discovered member of the nuclear hormone receptor family, were reported to cause X-linked congenital adrenal hypoplasia and hypogonadotrophic hypogonadism. While genetic data on DAX-1 are accumulating, information on the clinical course of the disorder are scarce. Here we present a detailed documentation of longitudinal data relating to three cases. We retrospectively collected clinical data on three boys (6, 14 and 14.5 years old) who we examined over a period ranging between 5 and 14 years. Mutational analysis of the DAX-1 gene was performed by means of direct sequencing of PCR products. The patients presented at ages between 4 and 6 weeks with salt-wasting, but there was no evidence of hypoglycaemia. All three cases were initially erroneously diagnosed with isolated aldosterone deficiency. Glucocorticoid deficiency was established by means of ACTH stimulation tests at 4 months, 3 and 13 years of age. One boy, whose therapy was discontinued at the age of 4 months, developed normally until adrenal crisis occurred at the age of 13 years. In all three cases, congenital hypogonadism was ruled out during infancy, as penis size was normal, the testes were descended, and serum samples contained normal testosterone levels. One boy exhibited transient hypergonadotrophism at age 9 but showed no clinical signs of puberty or an increase in serum testosterone. Onset of puberty and LHRH tests proved to be normal in his case as well as in another patient studied. In two patients, genetic analysis revealed new mutations at the C-terminus of DAX-1, these being a 1-base deletion (656delG) inherited from the mother and a de-novo 2-base insertion (728insCA) of the DAX-1 gene, respectively, both causing frame shift and premature stops at codons 263 and 398. One boy was affected by a new nonsense mutation of codon 39 (W39X) inherited from his mother. Mineralocorticoid deficiency preceded glucocorticoid deficiency which could be diagnosed through ACTH stimulation after the neonatal period. Transitory functional recovery of the adrenal glands can occur in adrenal hypoplasia congenita (AHC). Transient hypergonadotrophism may be one of the first indicators of defects in the gonadal axis, although normal initiation of puberty is not rare. The definitive diagnosis was established by means of molecular analysis of the DAX-1 gene. There was no correlation between types of mutations and phenotypes. The diagnostic procedure in male children and adolescents presenting with adrenal crisis should include ACTH stimulation tests and mutational analysis of DAX-1 in the absence of another proven aetiology.

Adolescent↗

PubMed2000

Scarf ratio: A method of measuring the Scarf sign in preterm born infants.

A new method of measuring the Scarf sign called the Scarf ratio is described in which data derived were reported on a continuous scale. The Scarf ratio is the distance of the olecranon process of the arm being tested as it moves across the trunk compared with the infant's own biacromial width. Longitudinal data for the Scarf ratio were measured in a cohort of 111 Thai preterm born infants. The data were collapsed into four age ranges ie 28-31, 32-36, 37-39 and 40 weeks post-conceptional age (PCA) according to the trends from the longitudinal plots. As the means of the Scarf ratio increased with age, it can be described that the resistance to the passive movements of the arm increased when the infants grew up. Data were also converted to a newly developed categorical scoring system. All infants between the age of 28 and 31 weeks PCA recorded a score of 1 (low tone). Most infants aged 32-36 and 37-39 weeks PCA recorded a score of 2 while most infants aged 40 weeks PCA obtained a score of 3 (high tone). Thus, this method can be an alternative when continuous data for the Scarf sign are desirable.

Journal Article↗

PubMed1989

Positron emission tomography in psychiatric and neuropsychiatric disorders.

PET is potentially the most powerful tool yet available for the direct, in vivo investigation of the biologic basis of psychiatric and neuropsychiatric disorders. The fulfillment of its potential rests on the development of methodologies and study design appropriate to psychiatric disorders. To date, findings in both schizophrenia and affective disorder, using protocols largely based on resting state data acquisition, suggest altered regional metabolism. These approaches need to be extended, particularly by the application of protocols that utilize PET to obtain longitudinal data under controlled experimental situations. In two conditions traditionally ascribed to psychologic causes, OCD and PD, there is intriguing evidence of specific biologic abnormalities, which, if confirmed, would lead to a fundamental revision of their nosologic status. In neuropsychiatric disorders PET findings, although preliminary in nature, offer an alternative paradigm to traditional clinicopathologic correlations by suggesting that clinical impairments relate to physiologic effects at sites distant from structural lesions.

Anxiety Disorders↗

PubMedDate not supplied

Differential aging: an exploratory approach using cluster analysis.

This article uses cluster analysis to identify different patterns of personal resources within a random sample of the well, elderly population. Ten such patterns or natural groupings are identified and their implications for coping and successful aging are discussed. It is apparent that there are a number of ways both of aging well and aging badly, and that these patterns cannot be predicted solely on the basis of structural data. The article poses a number of questions on the performance of cluster members over time and draws attention to the importance of longitudinal data.

Adaptation, Psychological↗

PubMedDate not supplied

Postural changes in dental hygienists. Four-year longitudinal study.

Numerous surveys identify the occurrence of musculoskeletal complaints as a concern in dentistry. However, no longitudinal data exist to indicate whether postural changes occur as a result of practicing dental hygiene. The purpose of this preliminary, four-year longitudinal study was to investigate whether any postural changes developed during the hygienists' clinical education and/or during subsequent dental hygiene practice after one and/or two years. It was anticipated that the awkward positions and intense physical demands placed on hygienists might initiate musculoskeletal problems, but that no postural changes would occur over this short period of time. Nine of 10 dental hygienists in the graduating class of 1987 were surveyed for existing musculoskeletal complaints, and the subjects were photographed for a measurement of postural change. Responses from participants indicated an increase in musculoskeletal-related complaints in each of the six areas investigated. The photographic findings indicated that one of the nine hygienists showed an increase in forward head posture, a postural change.

Adolescent↗

PubMed1996

The progression of myopia in school age children: data from the Columbia Medical Plan.

The purpose of this study was to characterize the clinical course of myopia in a selected pediatric population. The computerized records of a health maintenance organization provided longitudinal data on 501 children aged 5 to 15 years. We examined the influence of age at diagnosis, gender, race, and initial refraction on progression of myopia. Mean follow-up was 34 months, with 75% of children having follow-up longer than 16 months. The mean rate of myopic progression was greater for children whose myopia was diagnosed at a younger age (5-7 years, -0.56 diopters/year versus 11-15 years, -0.28 diopters/year; p < 0.0001). Children with more than one diopter of myopia at first diagnosis progressed faster than children with less than or equal to one diopter of myopia (mean rate -0.48 diopter/year versus -0.41 diopter/year; p = 0.05). Cumulative event rate curves suggest a gender effect in the prepuberty years of 8 to 10, with myopia progressing faster in girls than boys (p = 0.003). Progression of myopia did not differ between white and non-white children. More rapidly progression of myopia is associated with younger age at initial diagnosis and greater severity of initial myopic refraction.

Adolescent↗

PubMed2005

Variable selection for marginal longitudinal generalized linear models.

Variable selection is an essential part of any statistical analysis and yet has been somewhat neglected in the context of longitudinal data analysis. In this article, we propose a generalized version of Mallows's C(p) (GC(p)) suitable for use with both parametric and nonparametric models. GC(p) provides an estimate of a measure of model's adequacy for prediction. We examine its performance with popular marginal longitudinal models (fitted using GEE) and contrast results with what is typically done in practice: variable selection based on Wald-type or score-type tests. An application to real data further demonstrates the merits of our approach while at the same time emphasizing some important robust features inherent to GC(p).

Bias↗

PubMed1989

Epidemiology of fractures of the distal end of the radius in children as associated with growth.

We determined the annual incidence of fracture of the distal end of the radius for patients of all ages and both sexes in the province of Saskatchewan, using two data sets: data on hospital admissions for 1970 through 1984, and data on physician billing for 1978 through 1985. The rate of occurrence of this fracture in children, by age and sex, was compared with longitudinal data on the velocity of growth that was collected during the same time for children from the same population. We compared the incidences of the fracture with the results of studies on the levels of activity in children and adolescents during growth. We also compared the age-specific incidence of the fracture in children with the incidence in adults. For both data sets, the age at the peak incidence of fracture of the distal end of the radius almost perfectly matched the age at which peak velocity of growth in height occurs for boys and girls. For girls, the peak incidence occurred between the ages of 11.5 and 12.5 years and for boys, between 13.5 and 14.5 years; these ages corresponded to the mean peak velocity of growth at 11.9 years for girls and 14.3 years for boys. The age-adjusted incidence of the fracture in male subjects was highest at fourteen years and was not exceeded by that in female subjects until fifty-three to fifty-four years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed2006

Progression of radiographic joint damage in different eras: trends towards milder disease in rheumatoid arthritis are attributable to improved treatment.

BACKGROUND: Severity of rheumatoid arthritis and progression of radiographic joint damage have decreased over the last decades. AIM: To examine whether this trend is attributable to an underlying trend towards milder disease or to improved treatment. METHODS: The study used an inception cohort of patients with early rheumatoid arthritis seen at the Wichita Arthritis Center, Wichita, Kansas, USA, since 1973 and monitored prospectively since their first clinic visit through clinical, radiographic, laboratory, demographic and self-reported data. The radiographic disease progression in patients with disease onset in the 1970s, 1980s and 1990s was compared using a multivariate regression model for longitudinal data. The analysis was adjusted for differences in baseline predictors, type of disease-modifying antirheumatic drugs (DMARDs) and steroid use. RESULTS: 418 patients with rheumatoid arthritis with radiographic follow-up were included. Patients in earlier decades used fewer DMARDs, had longer disease durations and higher tender joint counts at their first visit. Other important predictors of disease progression did not differ significantly between decades of disease onset. The unadjusted rates of radiographic progression differed between decades (analysis of variance, p = 0.01), with a significant trend towards less radiographic progression in more recent times (trend, p<0.001). However, after adjusting for DMARD use, steroid use and baseline predictors, differences between decades vanished (analysis of variance, p = 0.40) and the trend towards less radiographic progression disappeared (trend, p = 0.45). CONCLUSION: These results suggest that the observed trend towards milder disease in rheumatoid arthritis is attributable to more effective antirheumatic treatment and not to a secular trend.

Adult↗

PubMed1994

Methods for quality-of-life studies.

Methodologies involving the use of quality-of-life patient outcomes in observational and interventional studies of health are drawn from a large and diverse field of research methods. The multidimensional way in which quality of life is conceptualized will affect the way it is measured and the complexity of the measurement. At the earliest stages of research, one must rely on methods common to the fields of tests and measurement, survey research, psychometrics and sociometrics to measure constructs that are not directly observable. Indices measuring performance can either focus on the scale's ability to perform in noninterventional, cross-sectional studies or interventional, longitudinal studies. Indices of stability, internal consistency, responsiveness with respect to true changes in quality of life, and sensitivity to treatment effects can be used to assess the scale's adequacy as a dependent variable of interest. Respondent variability can occur due to factors such as different reporters (patient, spouse, physician), the manner and form of administration (long form vs short form; self-administration vs interview) and the assessment environment (clinic, home). Finally, since quality-of-life research often involves inferential statistics and hypothesis testing, the statistical and epidemiologic principles of good study design should be followed. In addition, one should account for the reliability, responsiveness, and the sensitivity of the scale when designing the scientific hypotheses, and should specifically address the meaning of quality-of-life effect sizes by interventional-based validation. Design considerations must address the statistical issues of power, the determination of effect sizes through validation by external criteria, longitudinal data, effects of withdrawal and early termination, ceiling and floor effects, and heterogeneity of responsiveness and sensitivity among individuals. The problem of estimating quality-of-life summary parameters for use in pharmacoeconomic models is receiving increasing attention in this era of health-care reform and fiscal restraint. While medical decision theory has used cost-effectiveness models and quality-adjusted life years since the early 1970s, estimation of population parameters to differentiate among different medical interventions is relatively new. The assessment of the patient outcomes associated with medical interventions in terms of the risks, benefits and costs will clearly be a major focus of health-care reform. Development of new methodologies in quality-of-life research should build upon the strong foundation already established in the areas of clinical research, epidemiology, biostatistics, economics and behavioral science.(ABSTRACT TRUNCATED AT 400 WORDS)

Bias↗

PubMed2006

Longitudinal drinking patterns in indigenous Sami and non-indigenous youth in northern Norway.

Drinking patterns among indigenous Sami and non-Sami adolescents in northern Norway were explored. Longitudinal data were collected in 1994/95 among 2,950 high school students (RR: 85%) and in 1997/98 among 1,510 follow-ups (RR: 57%). Longitudinally, Sami had significantly lower drinking rates for all measures. An increase in 30-day drinkers occurred during the follow-up period: 23% in Sami and 19% in non-Sami. Sami reported higher paternal abstinence. Sami drank more often in public places. Sami reported more worries from friends and family about their drinking. The lower drinking rates in Sami relative to majority adolescents contrast with findings among indigenous peers elsewhere, but corresponds with the lower parental drinking rates.

Adolescent↗

PubMedDate not supplied

Developmental outcome of children born to methadone maintained women: a review of longitudinal studies.

The purpose of this review is first to present current longitudinal data on the developmental outcome of children born to drug dependent women maintained on methadone and, second, to focus on methodological problems within this area of research. Five longitudinal studies which evaluated methadone exposed infants throughout the first two years of life are reviewed. The results of these studies suggest that no long term developmental sequelae are directly associated with methadone exposure in-utero. Although differences were often found between methadone exposed infants and comparison infants on the Bayley Scales of Infant Development, scores for the methadone exposed infants were well within the normal range of development. Existing data on methadone exposed children at 4 years of age are reviewed. No differences in cognitive performance were found between methadone exposed and comparison children although scores for both groups were low. Problems with confounding variables and the inappropriate use of a main effects model of development in this area of research are addressed and the need to investigate socioenvironmental risk factors in order to fully understand the development of children exposed to methadone in-utero is discussed.

Child Development↗

PubMed2005

Assessment of skeletal development in preterm and term infants by quantitative ultrasound.

Assessment of skeletal development using a nonionizing method would be desirable in critically ill preterm infants. We investigated the second metacarpus by quantitative ultrasound (QUS). Cross-sectional data were collected in 132 preterm or term infants measured within 24 h from birth and in 142 term infants up to the age of 18 mo. Longitudinal data were collected in 150 preterm infants up to the age of 14 mo. Cross-sectional data were used to devise reference curves for metacarpal speed of sound (mcSOS) and metacarpal bone transmission time (mcBTT). Both parameters increase during the last trimester of gestation. After birth, mcSOS declines up to the 6 mo and then increases up to 18 mo of life. McBTT values remain stable after birth. At birth, QUS values of preterm infants are lower than those observed at birth in term infants. In the longitudinal study, mcSOS showed a trend similar to that observed among term infants, nevertheless, values are lower up to 4-6 mo of life. Among preterm infants, mcBTT increases until it reaches values observed in term infants. Preterm infants in their first months of life have lower QUS values compared with term infants of same weight or length. This study demonstrates that it is possible to follow skeletal development and maturation by QUS in preterm infants. More specifically, the mcBTT values may provide information on bone tissue that is independent of length and weight of the preterm infant. The method here described is safe, repeatable, and reliable.

Absorptiometry, Photon↗

PubMed1992

Foveal dark adaptation, photopigment regeneration, and aging.

Foveal dark adaptation in 58 subjects and photopigment regeneration in 60 subjects from 10-78 years of age exhibit parallel slowing of recovery rate with increasing age, with significant correlation of the two functions among individuals. The data are suggestive of an initial slight decline in rate before age 50, followed by a greater decline occurring at different ages in different individuals. Longitudinal data for one subject from age 40-65 show an increase in pigment regeneration time constant consistent with this idea. Foveal sensitivity and photopigment density both decrease with increasing age and are significantly correlated among individuals, although sensitivity declines more with age than does photopigment density. In contrast to earlier proposals based upon the Rushton-Dowling equation, we found no universal constant of proportionality to relate log relative threshold to photopigment within our population.

Adolescent↗