Group-based trajectory modeling in clinical research

Young adult weight trajectories through midlife by body mass category

OBJECTIVE

To estimate the expected weight gain through midlife for those in a given BMI category in young adulthood.

DESIGN AND METHODS

Group-based trajectory modeling and National Longitudinal Survey of Youth 1979 data from 1990 to 2008 were used to quantify weight trajectories through midlife for 10,038 young adult men and women stratified by BMI category. Logistic regression was used to assess the association of trajectory membership with obesity-related conditions (hypertension, diabetes, arthritis) in middle age.

RESULTS

Annual weight gain averaged 0.53 kg (1.17 lb) across the entire sample. However, there was considerable variation by and within BMI categories. More than 98% of men and 92% of women were on upward-sloping trajectories, generally moving into a higher BMI category by middle age. Those who experienced early and rapid weight gain during young adulthood were most likely to be on a steeper trajectory and had greater risks for obesity-related conditions.

CONCLUSION

This study points to the health and weight benefits of entering young adulthood with a normal BMI, but further reveals that this is no guarantee of maintaining a healthy weight through midlife. For those who are young adults today, weight maintenance is unlikely to occur without significant environmental or technical innovation.

Temporal trends in symptom experience predict the accuracy of recall PROs

OBJECTIVE

Patient-reported outcome measures with reporting periods of a week or more are often used to evaluate the change of symptoms over time, but the accuracy of recall in the context of change is not well understood. This study examined whether temporal trends in symptoms that occur during the reporting period impact the accuracy of 7-day recall reports.

METHODS

Women with premenstrual symptoms (n=95) completed daily reports of anger, depression, fatigue, and pain intensity for 4weeks, as well as 7-day recall reports at the end of each week. Latent class growth analysis was used to categorize recall periods based on the direction and rate of change in the daily reports. Agreement (level differences and correlations) between 7-day recall and aggregated daily scores was compared for recall periods with different temporal trends.

RESULTS

Recall periods with positive, negative, and flat temporal trends were identified and they varied in accordance with weeks of the menstrual cycle. Replicating previous research, 7-day recall scores were consistently higher than aggregated daily scores, but this level difference was more pronounced for recall periods involving positive and negative trends compared with flat trends. Moreover, correlations between 7-day recall and aggregated daily scores were lower in the presence of positive and negative trends compared with flat trends. These findings were largely consistent for anger, depression, fatigue, and pain intensity.

CONCLUSION

Temporal trends in symptoms can influence the accuracy of recall reports and this should be considered in research designs involving change.

Long-term functional benefits of selective dorsal rhizotomy for spastic cerebral palsy

OBJECT

Large-scale natural history studies of gross motor development have shown that children with spastic cerebral palsy (CP) plateau during childhood and actually decline through adolescence. Selective dorsal rhizotomy (SDR) is a well-recognized treatment for spastic CP, but little is known about long-term outcomes of this treatment. The purpose of this study was to assess the durability of functional outcomes in a large number of patients through adolescence and into early adulthood using standardized assessment tools.

METHODS

The authors analyzed long-term follow-up data in children who had been evaluated by a multidisciplinary team preoperatively and at 1, 5, 10, and 15 years after SDR. These evaluations included quantitative, standardized assessments of lower-limb tone (Ashworth Scale), Gross Motor Function Measure (GMFM), and performance of activities of daily living (ADLs) by the Pediatric Evaluation of Disability Inventory in children who had been stratified by motor severity using the Gross Motor Function Classification System (GMFCS). In addition, group-based trajectory modeling (GBTM) was used to identify any heterogeneity of response to SDR among these treated children, and to find which pretreatment variables might be associated with this heterogeneity. Finally, a chart review of adjunct orthopedic procedures required by these children following SDR was performed.

RESULTS

Of 102 patients who underwent preoperative evaluations, 97, 62, 57, and 14 patients completed postoperative assessments at 1, 5, 10, and 15 years, respectively. After SDR, through adolescence and into early adulthood, statistically significant durable improvements in lower-limb muscle tone, gross motor function, and performance of ADLs were found. When stratified by the GMFCS, long-lasting improvements for GMFCS Groups I, II, and III were found. The GBTM revealed 4 groups of patients who responded differently to SDR. This group assignment was associated with distribution of spasticity (diplegia was associated with better outcomes than triplegia or quadriplegia) and degree of hip adductor spasticity (Ashworth score < 3 was associated with better outcomes than a score of 3), but not with age, sex, degree of ankle plantar flexion spasticity, or degree of hamstring spasticity. In a sample of 88 patients who had complete records of orthopedic procedures and botulinum toxin (Botox) injections, 52 (59.1%) underwent SDR alone, 11 (12.5%) received only Botox injections in addition to SDR, while 25 patients (28.4%) needed further lower-extremity orthopedic surgery after SDR.

CONCLUSIONS

In the majority of patients, the benefits of SDR are durable through adolescence and into early adulthood. These benefits include improved muscle tone, gross motor function, and performance of ADLs, as well as a decreased need for adjunct orthopedic procedures or Botox injections. The children most likely to display these long-term benefits are those in GMFCS Groups I, II, and III, with spastic diplegia, less hip adductor spasticity, and preoperative GMFM scores greater than 60.

The natural history of periodontal attachment loss during the third and fourth decades of life

AIM

To describe changes in the occurrence of periodontal attachment loss (AL) through ages 26, 32 and 38 in a complete birth cohort.

MATERIALS AND METHODS

Systematic periodontal examinations conducted at ages 26, 32 and 38 in a longstanding New Zealand cohort study (N = 1037). Periodontitis extent data were used to assign participants to periodontitis trajectories using group-based trajectory analysis.

RESULTS

Eight hundred and thirty-one individuals were periodontally examined at all three ages; the prevalence and extent of AL increased as the cohort aged. Between 26 and 32, one in nine participants had 1+ sites showing new or progressing AL; that proportion almost doubled between ages 32 and 38. Four periodontitis trajectory groups were identified, comprising 55.2%, 31.5%, 10.7% and 2.5% of the cohort; these were termed the "Very low", "Low", "Moderately increasing" and "Markedly increasing" trajectory groups respectively. Those who had smoked tobacco at all ages from 15 through 38 were at higher risk of being in the "Moderately increasing" or "Markedly increasing" trajectory groups. There was a similar risk gradient for those who were in the highest 20% of cannabis usage.

CONCLUSIONS

Periodontitis commences relatively early in adulthood, and its progression accelerates with age, particularly among smokers.

The longitudinal relationship between sleep duration and body mass index in children: a growth mixture modeling approach

OBJECTIVE

A growing number of studies indicate that shorter sleep durations could contribute to obesity in children. The objective of this article was to further examine the longitudinal relationship between sleep duration and body mass index (BMI) in children by using a growth mixture modeling approach.

METHOD

This article used prospective data from the Longitudinal Study of Australian Children. Participants included 1079 children aged 4 to 5 years (2004) followed up until age 10 to 11 years (2010). Growth mixture modeling was performed to examine the longitudinal association between sleep duration and body mass index within distinct body mass index trajectories.

RESULTS

The results indicated 3 distinct body mass index trajectories: healthy weight, early onset obesity, and later onset obesity. Longitudinal inverse associations were evident between sleep duration and body mass index in the Early Onset Trajectory. There were some associations between sleep duration and body mass index in the other trajectories.

CONCLUSIONS

This article provides further insight into the longitudinal relationship between sleep duration and body mass index in children. In particular, the results indicate that shorter sleep durations are primarily associated with body mass index in children with early onset obesity.

A graphical method to assess distribution assumption in group-based trajectory models

Group-based trajectory models had a rapid development in the analysis of longitudinal data in clinical research. In these models, the assumption of homoscedasticity of the residuals is frequently made but this assumption is not always met. We developed here an easy-to-perform graphical method to assess the assumption of homoscedasticity of the residuals to apply especially in group-based trajectory models. The method is based on drawing an envelope to visualize the local dispersion of the residuals around each typical trajectory. Its efficiency is demonstrated using data on CD4 lymphocyte counts in patients with human immunodeficiency virus put on antiretroviral therapy. Four distinct distributions that take into account increasing parts of the variability of the observed data are presented. Significant differences in group structures and trajectory patterns were found according to the chosen distribution. These differences might have large impacts on the final trajectories and their characteristics; thus on potential medical decisions. With a single glance, the graphical criteria allow the choice of the distribution that best capture data variability and help dealing with a potential heteroscedasticity problem.

Group-based trajectory modeling: a novel approach to examining symptom trajectories in acute bipolar episodes

BACKGROUND

Pattern analysis can aid understanding of trajectories of symptom evolution. However, most studies focus on relatively homogeneous disorders with a restricted range of outcomes, prescribed a limited number of classes of medication. We explored the utility of pattern analysis in defining short-term outcomes in a heterogeneous clinical sample with acute bipolar disorders.

METHOD

In a naturalistic observational study, we used Group-based trajectory modeling (GBTM) to define trajectories of symptom change in 118 bipolar cases recruited during an acute DSM IV episode: major depression (56%), (hypo)mania (26%), and mixed states (18%). Symptoms were assessed weekly for a month using the MATHYS, which measures symptoms independent of episode polarity.

RESULTS

Four trajectories of symptom change were identified: Persistent Inhibition, Transient Inhibition, Transient Activation and Over-activation. However, counter to traditional predictions, we observed that bipolar depression shows a heterogeneous response pattern with cases being distributed approximately equally across trajectories that commenced with inhibition and activation.

LIMITATIONS

The observational period focuses on acute outcomes and so we cannot use the findings to predict whether the trajectories lead to stable improvement or whether the clinical course for some clusters is cyclical. As in all GBTM, the terms used for each trajectory are subjective, also the modeling programme we used assumes dropouts are random, which is clearly not always the case.

CONCLUSION

This paper highlights the potential importance of techniques such as GBTM in distinguishing the different response trajectories for acutely ill bipolar cases. The use of the MATHYS provides further critical insights, demonstrating that clustering of cases with similar response patterns may be independent of episodes defined by mood state.

Association of impaired linear growth and worse neurodevelopmental outcome in infants with single ventricle physiology: a report from the pediatric heart network infant single ventricle trial

OBJECTIVES

To describe neurodevelopmental outcomes in infants with single ventricle (SV) physiology and determine factors associated with worse outcomes.

STUDY DESIGN

Neurodevelopmental outcomes for infants with SV enrolled in a multicenter drug trial were assessed at 14 months of age using the Bayley Scales of Infant Development-II. Multivariable regression analysis was used to identify factors associated with worse outcomes.

RESULTS

Neurodevelopmental testing was performed at 14 ± 1 months in 170/185 subjects in the trial. Hypoplastic left heart syndrome was present in 59% and 75% had undergone the Norwood operation. Mean Psychomotor Developmental Index (PDI) and mental developmental index (MDI) were 80 ± 18 and 96 ± 14, respectively, (normal 100 ± 15, P < .001 for each). Group-based trajectory analysis provided a 2-group model ("high" and "low") for height z-score trajectory and brain type natriuretic peptide (BNP) trajectory. The predicted PDI scores were 15 points higher in the "high" height z-score trajectory compared with the "low" cluster (P < .001). A higher number of serious adverse events during the trial was associated with lower PDI scores (P = .02). The predicted MDI scores were 13-17 points lower in "low height trajectory-high BNP trajectory" group compared with the other 3 groups (P < .001). MDI scores were also lower in subjects who required extracorporeal membrane oxygenation during the neonatal hospitalization (P = .01) or supplemental oxygen at discharge (P = .01).

CONCLUSIONS

Neurodevelopmental outcome at 14 months of age is impaired in infants with SV physiology. Low height trajectory and high BNP trajectory were associated with worse neurodevelopmental outcomes. Efforts to improve nutritional status alone may not improve neurodevelopmental outcomes.

Patterns of treatment utilization and methamphetamine use during first 10 years after methamphetamine initiation

The study examined joint trajectories of methamphetamine (MA) use and substance abuse treatment utilization and identified differences among pattern groups for a sample of 348 treated for MA use. Results from group-based trajectory modeling showed that treatment utilization during the first 10 years after initiation of MA use could be categorized into three distinctive patterns: about half the MA users have a pattern of low treatment utilization; one-fourth follow a quicker-to-treatment trajectory with higher probability of treatment during the first 5 years of MA use and less treatment in the next 5 years; and one-fourth have a slower-to-treatment trajectory with more treatment during the second half of the 10-year period. Four MA use patterns were identified: consistently low use, moderate, and high use, as well as a decreasing use pattern. Periods of greater likelihood of treatment participation were associated with periods of decreasing or lower frequency of MA use.

Linking childhood sexual abuse and early adolescent risk behavior: the intervening role of internalizing and externalizing problems

A robust literature links childhood sexual abuse (CSA) to later substance use and sexual risk behavior; yet, relatively little empirical attention has been devoted to identifying the mechanisms linking CSA to risky behavior among youth, with even less work examining such processes in boys. With the aim of addressing this gap in the literature, the current study examined the indirect effect of childhood sexual abuse (CSA; from age 2 to 12) trajectory group on risky behavior at age 14 (alcohol use & sexual intercourse) via the intervening role of caregiver-reported internalizing and externalizing problems at age 12. Analyses were conducted with a subsample of youth (n = 657 sexual intercourse; n = 667 alcohol use) from the Longitudinal Studies of Child Abuse and Neglect (LONGSCAN), a multisite prospective study of youth at risk for maltreatment. For boys and girls, there was an indirect effect from CSA to sexual intercourse through externalizing problems. The same pattern emerged for alcohol use, but only for girls. Findings did not support an indirect path through internalizing problems for either boys or girls for either outcome. Findings suggest more focal targets for prevention efforts aimed at maintaining the health and safety of maltreated boys and girls during the adolescent transition.

Trajectories of response to treatment for posttraumatic stress disorder

Research on the predictors of response to cognitive-behavioral treatments for PTSD has often produced inconsistent or ambiguous results. We argue this is in part due to the use of statistical techniques that explore relationships among the entire sample of participants rather than homogeneous subgroups. Using 2 large randomized controlled trials of Cognitive Processing Therapy (CPT), CPT components, and Prolonged Exposure, we employed growth mixture modeling to identify distinct trajectories of treatment response and to determine the predictors of those trajectories. We determined that the participants' trajectories could be best represented by 2 latent classes, which we subsequently labeled responders (87% of the sample) and nonresponders (13% of the sample). Notably, there was not a separate class for partial responders. Assignment to the nonresponder class was associated with receiving the written accounts (WA) component of CPT, a pretreatment diagnosis of major depression (MDD), and more pretreatment hyperarousal symptoms. Thus, it appears that some individuals do not benefit from merely writing about their trauma and processing it with the therapist; they may also need to engage in cognitive restructuring to successfully ameliorate their symptoms. Additionally, those who meet criteria for MDD or have high levels of hyperarousal at the onset of treatment might require additional treatment or support.

Group-based trajectory modeling of caregiver psychological distress over time

BACKGROUND

Competing theories of adaptation and wear-and-tear describe psychological distress patterns among family caregivers.

PURPOSE

This study seeks to characterize psychological distress patterns in family caregivers and identify predictors.

METHODS

One hundred three caregivers of care recipients with primary malignant brain tumors were interviewed within 1, 4, 8, and 12 months post-diagnosis regarding psychological distress; care recipients were interviewed regarding clinical/functional characteristics. Group-based trajectory modeling identified longitudinal distress patterns, and weighted logistic/multinomial regression models identified predictors of distress trajectories.

RESULTS

Group-based trajectory modeling identified high-decreasing (51.1 % of caregivers) and consistently low (48.9 %) depressive symptom trajectories, high-decreasing (75.5 %) and low-decreasing (24.5 %) anxiety trajectories, and high (37.5 %), moderate (40.9 %), and low-decreasing (21.6 %) caregiver burden trajectories. High depressive symptoms were associated with high trajectories for both anxiety and burden, lower caregivers age, income, and social support, and lower care recipient functioning.

CONCLUSIONS

Our data support the adaptation hypothesis; interventions should target those at risk for persistent distress.

Use of a mixture statistical model in studying malaria vectors density

Vector control is a major step in the process of malaria control and elimination. This requires vector counts and appropriate statistical analyses of these counts. However, vector counts are often overdispersed. A non-parametric mixture of Poisson model (NPMP) is proposed to allow for overdispersion and better describe vector distribution. Mosquito collections using the Human Landing Catches as well as collection of environmental and climatic data were carried out from January to December 2009 in 28 villages in Southern Benin. A NPMP regression model with “village” as random effect is used to test statistical correlations between malaria vectors density and environmental and climatic factors. Furthermore, the villages were ranked using the latent classes derived from the NPMP model. Based on this classification of the villages, the impacts of four vector control strategies implemented in the villages were compared. Vector counts were highly variable and overdispersed with important proportion of zeros (75%). The NPMP model had a good aptitude to predict the observed values and showed that: i) proximity to freshwater body, market gardening, and high levels of rain were associated with high vector density; ii) water conveyance, cattle breeding, vegetation index were associated with low vector density. The 28 villages could then be ranked according to the mean vector number as estimated by the random part of the model after adjustment on all covariates. The NPMP model made it possible to describe the distribution of the vector across the study area. The villages were ranked according to the mean vector density after taking into account the most important covariates. This study demonstrates the necessity and possibility of adapting methods of vector counting and sampling to each setting.

Maternal anaemia at delivery and haemoglobin evolution in children during their first 18 months of life using latent class analysis

Background

Anaemia during pregnancy and at delivery is an important public health problem in low- and middle-income countries. Its association with the children’s haemoglobin level over time remains unclear. Our goals were to identify distinct haemoglobin level trajectories using latent class analysis and to assess the association between these trajectories and maternal anaemia and other risk factors.

Method

A prospective study of children from birth to 18 months of life was conducted in a rural setting in Tori-Bossito, Benin. The main outcome measure was the haemoglobin levels repeatedly measured at 3, 6, 9, 12, 15 and 18 months. Variables were collected from the mothers at delivery and from their children at birth and during the follow-up. The analyses were performed by means of Latent Class Analysis which has never been used for this kind of data. All the analyses were performed with Stata software, version 11.0, using the generalized linear latent and mixed model (GLLAMM) framework.

Results

We showed that 33.7% of children followed a low haemoglobin trajectory and 66.3% a high trajectory during the first 18 months of life. Newborn anaemia, placental malaria, malaria attack, sickle cell trait and male gender were significantly associated with a lower children’s haemoglobin level over time, whereas maternal age, children living in a polygamous family and with good feeding practices had a higher Hb level in the first18 months. We also showed that maternal anaemia was a predictor for ‘low haemoglobin level trajectory’ group membership but have no significant effect on children haemoglobin level over time.

Conclusion

Latent Class Analyses framework seems well suited to analyse longitudinal data under the hypothesis that different subpopulations of subjects are present in the data, each with its own set of parameters, with distinctive evolutions that themselves may reflect distinctive aetiologies.

Can patterns of alcohol use disorder in young adulthood help explain gender differences in depression?

OBJECTIVE

To test whether gender differences in the prevalence of major depressive disorder differ by longitudinal patterns of alcohol use disorder symptoms.

METHOD

Data are from a prospective longitudinal study examining a broad range of mental health and substance use problems. A gender-balanced sample of 808 participants was interviewed at ages 21, 24, 27, and 30. The sample was divided into subgroups corresponding to longitudinal patterns of alcohol use disorder derived from latent class growth analysis.

RESULTS

Four patterns of alcohol use disorder symptoms were identified: A "low disorder symptom" group, a "decreaser" group, an "increaser" group, and a "chronic disorder symptom" group. Rates of depression were significantly higher for females only among those with a pattern of chronic or decreasing alcohol disorder symptoms.

CONCLUSIONS

Elevated rates of depression among females in young adulthood may depend on patterns of co-occurring alcohol disorder symptoms. Practitioners should pay particular attention to signs of chronic alcohol use disorders and associated risks for depression among young adult women.

Psychological dating violence perpetration and victimization: trajectories from middle to high school

Despite evidence documenting the negative consequences, psychological dating violence occurs frequently in adolescent dating relationships. No information exists on the trajectories that adolescents follow and their association to nonphysical peer violence. The sample comprised 624 randomly selected 6th graders. In yearly surveys from 6th through 12th grade, 550 of the 624 students reported dating at least twice during the 3 months prior to completing the survey. These students responded to questions about frequency of engagement in psychological dating violence perpetration and victimization. We used Proc TRAJ to identify developmental trajectories of behavior over time and generalized estimating equation models to examine the associations of the trajectories and peer aggression. Adolescents followed three distinct developmental trajectories related to psychological dating violence victimization and perpetration: low, increasing, and high. Based on the joint probabilities of victimization and perpetration, we identified four predominant groups: low victimization/low perpetration (LVLP; 36%), increasing victimization/increasing perpetration (40%), high victimization/high perpetration (HVHP; 15%), and increasing victimization/low perpetration (IVLP; 7%). The LVLP had significantly more boys and White students; the HVHP group had an even gender distribution and more African-American students. For all groups, peer aggression decreased from Grade 6 to 12; students in the HVHP group reported the highest peer aggression, and students in the LVLP reported the lowest peer aggression. Findings suggest a strong, reciprocal relationship in the developmental trajectories of adolescents who experience and perpetrate psychological dating violence. Those highly engaged in these behaviors were also more likely to be violent toward peers.

Trajectories of childhood weight gain: the relative importance of local environment versus individual social and early life factors

OBJECTIVE

To determine the association between local environmental factors with child weight status in a longitudinal study, using a semi-parametric, group-based method, while also considering social and early life factors.

METHODS

Standardized, directly measured BMI from 4-10 y of age, and group-based trajectory modeling (PROC TRAJ) were used to estimate developmental trajectories of weight change in a Québec birth cohort (n = 1,566). Associations between the weight trajectories and living location, social cohesion, disorder, and material and social deprivation were estimated after controlling for social and early life factors.

RESULTS

FOUR WEIGHT TRAJECTORY GROUPS WERE ESTIMATED: low-increasing (9.7%); low-medium, accelerating (36.2%); medium-high, increasing (43.0%); and high-stable (11.1%). In the low-increasing and medium-high trajectory groups, living in a semi-urban area was inversely related to weight, while living in a rural area was positively related to weight in the high-stable group. Disorder was inversely related to weight in the low-increasing group only. Other important risk factors for high-stable weight included obesity status of the mother, smoking during pregnancy, and overeating behaviors.

CONCLUSIONS

In this study, associations between local environment factors and weight differed by trajectory group. Early life factors appear to play a more consistent role in weight status. Further work is needed to determine the influence of place on child weight.

Trajectories of cigarette smoking in adulthood predict insomnia among women in late mid-life

OBJECTIVE

To examine the relationship between trajectories of cigarette smoking among a community sample of women (N=498) with insomnia in late mid-life.

METHODS

Participants were administered structured interviews at four time waves in adulthood, spanning approximately 25 years (mean ages=40, 43, 48, and 65 years). At each wave, data were collected on participants' cigarette smoking. At the most recent time wave, in late mid-life, participants reported on their insomnia (difficulty falling asleep, staying asleep, early morning wakening, and daytime consequences of these sleep problems).

RESULTS

Growth mixture modeling extracted four trajectory groups of cigarette smoking (from mean ages 40-65 years): chronic heavy smokers, moderate smokers, late quitters, and non-smokers. Multivariate logistic regression analysis then examined the relationship between participants' probabilities of trajectory group membership and insomnia in late mid-life, with controls for age, educational level, marital status, depressive symptoms, body mass index, and the number of health conditions. Compared with the non-smokers group, members of the chronic heavy smoking trajectory group were more likely to report insomnia at mean age 65 (Adjusted Odds Ratio=2.76; 95% confidence interval=1.10-6.92; p<0.05).

CONCLUSIONS

Smoking cessation programs and clinicians treating female patients in mid-life should be aware that chronic heavy smoking in adulthood is a significant risk factor for insomnia.

Developmental trajectories of physical and indirect aggression from late childhood to adolescence: sex differences and outcomes in emerging adulthood

OBJECTIVE

Two common subtypes of aggression (physical and indirect) have been shown to develop concurrently throughout childhood and to uniquely predict maladjustment. However, nothing is known about psychiatric outcomes of joint trajectories of physical aggression (PA) and indirect aggression (IA) in emerging adulthood.

METHOD

Trajectories of PA and IA across ages 10 to 15 were modeled using 2,338 youth drawn from the National Longitudinal Study of Children and Youth. The identified trajectories were then used to predict delinquency problems, depressive symptoms, and emotional intelligence in emerging adulthood.

RESULTS

Three groups of children with distinct developmental trajectories of PA (no PA, 32.5%; moderate-declining PA 52.2%; and high-increasing PA, 15.3%) and three distinct developmental trajectories of IA (low-declining IA, 29.9%; moderate-declining IA, 65.5%; and high IA, 4.6%) were identified. Joint trajectories indicate that the largest group of children (41.6%) followed a moderate-declining IA trajectory and moderate-declining PA trajectory. Virtually no children were high on one type and low on the other. The proportion of boys was higher in the low IA-moderate declining PA and moderate IA-high increasing PA groups, whereas girls were more likely to be in the low IA-low PA and moderate IA-low PA groups. Individuals who followed elevated trajectories of IA and PA had significantly more depressive and delinquency symptoms and lower emotional quotient scores in emerging adulthood compared with those with lower trajectories.

CONCLUSIONS

These results suggest that some children have high PA and IA trajectories from childhood to adolescence and that these trajectories are associated with an increased risk for maladjustment.

Genetic influences on developmental smoking trajectories

AIMS

To investigate the relative contribution of genetic and environmental factors on smoking trajectory membership and to test whether individual smoking trajectories represent phenotypical thresholds of increasing genetic risk along a common genetic liability dimension.

DESIGN

Prospective study of a birth cohort of female like-sex twin pairs.

SETTING

Participants completed diagnostic interview surveys four times from adolescence (average age 16) to young adulthood (average age 25).

PARTICIPANTS

Female twins who had smoked ≥100 cigarettes life-time (n = 1466 regular smokers).

MEASUREMENTS

Number of cigarettes smoked per day during the heaviest period of smoking (two waves) or during the past 12 months (two waves).

FINDINGS

A four-trajectory class solution provided the best fit to cigarette consumption data and was characterized by low (n = 564, 38.47%), moderate (n = 366, 24.97%) and high-level smokers (n = 197, 13.44%), and smokers who increased their smoking from adolescence to young adulthood (n =339, 23.12%). The best genetic model fit was a three-category model that comprised the low, a combined increasing + moderate and high trajectories. This trajectory categorization was heritable (72.7%), with no evidence for significant contribution from shared environmental factors.

CONCLUSIONS

The way in which smoking patterns develop in adolescence has a high level of heritability.

Trajectories of maltreatment re-reports from ages 4 to 12:: evidence for persistent risk after early exposure

This study identified trajectories of maltreatment re-reports between ages 4 and 12 for children first referred to Child Protective Services (CPS) for maltreatment prior to age 4 and either removed from the home or assessed by a CPS intake worker as moderately or highly likely to be abused/neglected in the future, absent intervention. Participants (n = 501) were children from the Southwest and Northwest sites of the Consortium for Longitudinal Studies of Child Abuse and Neglect (LONGSCAN). During the 8-year follow-up period, 67% of children were re-reported. Growth mixture modeling identified four trajectory classes: No re-report (33%), Continuous re-reports (10%), Intermittent re-reports (37%), and Early re-reports (20%). Membership in classes with relatively more re-reports was predicted by several factors assessed at age 4, including physical abuse; living with a biological/stepparent; caregiver alcohol abuse, depression, and lack of social support; receipt of Aid to Families with Dependent Children (AFDC); and number of children in the home. For a subpopulation of high-risk children first reported in early childhood, risk for maltreatment re-reporting may persist longer than previously documented, continuing 8 to 12 years after the first report.

Trajectory clustering of estradiol and follicle-stimulating hormone during the menopausal transition among women in the Study of Women's Health across the Nation (SWAN)

CONTEXT

Variability in the pattern of change in estradiol (E2) and FSH levels over the menopause transition has not been well defined.

OBJECTIVE

The current study aimed to determine whether different trajectories of E2 and FSH could be identified and whether race/ethnicity and body mass index were related to the different trajectories.

DESIGN

The Study of Women's Health Across the Nation is a longitudinal observational study of the menopausal transition.

SETTING

Women aged 42-52 yr from seven participating sites were recruited and underwent up to 11 annual visits.

PARTICIPANTS

Postmenopausal women with 12 or more months of amenorrhea that was not due to hysterectomy/oophorectomy and who were not using hormone therapy before the final menstrual period participated in the study.

MAIN OUTCOME MEASURES

Annual serum E2 and FSH levels anchored to final menstrual period were measured.

RESULTS

Four distinct E2 trajectories and three distinct FSH trajectories were identified. The E2 trajectories were: slow decline (26.9%), flat (28.6%), rise/slow decline (13.1%), and rise/steep decline (31.5%). The FSH trajectories were: low (10.6%), medium (48.7%), and high (41.7%) rising patterns. Obesity increased the likelihood of a flat E2 and low FSH trajectory for all race/ethnic groups. Normal-weight Caucasian and African-American women tended to follow the rise/steep decline E2 and high FSH trajectories. Normal-weight Chinese/Japanese women tended to follow the slow decline E2 and the high/medium FSH trajectories.

CONCLUSIONS

E2 and FSH trajectories over the menopausal transition are not uniform across the population of women. Race/ethnicity and body mass index affect the trajectory of both E2 and FSH change over the menopausal transition.

Investigating clinical heterogeneity in systematic reviews: a methodologic review of guidance in the literature

BACKGROUND

While there is some consensus on methods for investigating statistical and methodological heterogeneity, little attention has been paid to clinical aspects of heterogeneity. The objective of this study is to summarize and collate suggested methods for investigating clinical heterogeneity in systematic reviews.

METHODS

We searched databases (Medline, EMBASE, CINAHL, Cochrane Library, and CONSORT, to December 2010) and reference lists and contacted experts to identify resources providing suggestions for investigating clinical heterogeneity between controlled clinical trials included in systematic reviews. We extracted recommendations, assessed resources for risk of bias, and collated the recommendations.

RESULTS

One hundred and one resources were collected, including narrative reviews, methodological reviews, statistical methods papers, and textbooks. These resources generally had a low risk of bias, but there was minimal consensus among them. Resources suggested that planned investigations of clinical heterogeneity should be made explicit in the protocol of the review; clinical experts should be included on the review team; a set of clinical covariates should be chosen considering variables from the participant level, intervention level, outcome level, research setting, or others unique to the research question; covariates should have a clear scientific rationale; there should be a sufficient number of trials per covariate; and results of any such investigations should be interpreted with caution.

CONCLUSIONS

Though the consensus was minimal, there were many recommendations in the literature for investigating clinical heterogeneity in systematic reviews. Formal recommendations for investigating clinical heterogeneity in systematic reviews of controlled trials are required.

Trajectories of drug use and mortality outcomes among adults followed over 18 years

BACKGROUND

For adults in general population community settings, data regarding long-term course and outcomes of illicit drug use are sparse, limiting the formulation of evidence-based recommendations for drug use screening of adults in primary care.

OBJECTIVE

To describe trajectories of three illicit drugs (cocaine, opioids, amphetamines) among adults in community settings, and to assess their relation to all-cause mortality.

DESIGN

Longitudinal cohort, 1987/88-2005/06.

SETTING

Community-based recruitment from four cities (Birmingham, Chicago, Oakland, Minneapolis).

PARTICIPANTS

Healthy adults, balanced for race (black and white) and gender were assessed for drug use from 1987/88-2005/06, and for mortality through 12/31/2008 (n = 4301)

MEASUREMENTS

Use of cocaine, amphetamines, and opioids (last 30 days) was queried in the following years: 1987/88, 1990/91, 1992/93, 1995/96, 2000/01, 2005/06. Survey-based assessment of demographics and psychosocial characteristics. Mortality over 18 years.

RESULTS

Trajectory analysis identified four groups: Nonusers (n = 3691, 85.8%), Early Occasional Users (n = 340, 7.9%), Persistent Occasional Users (n = 160, 3.7%), and Early Frequent/Later Occasional Users (n = 110, 2.6%). Trajectories conformed to expected patterns regarding demographics, other substance use, family background and education. Adjusting for demographics, baseline health status, health behaviors (alcohol, tobacco), and psychosocial characteristics, Early Frequent/Later Occasional Users had greater all-cause mortality (Hazard Ratio, HR = 4.94, 95% CI = 1.58-15.51, p = 0.006).

LIMITATIONS

Study is restricted to three common drugs, and trajectory analyses represent statistical approximations rather than identifiable "types". Causal inferences are tentative.

CONCLUSIONS

Four trajectories describe illicit drug use from young adulthood to middle age. Two trajectories, representing over one third of adult users, continued use into middle age. These persons were more likely to continue harmful risk behaviors such as smoking, and more likely to die.

The Role of Educational Aspirations and Expectations in the Discontinuity of Low-income Status Between Generations

The present study investigates one potential mechanism mediating continuity and discontinuity in low-income status across generations: children's educational aspirations and expectations. Data are drawn from a community sample of 808 students followed from age 10 into their 30s. Four subgroups of trajectories of children's educational expectations and aspirations were identified from ages 10 to 18: a "stable high" group, a "stable low" group, an "increaser" group, and a "decreaser" group. Among youths from low-income families, those in the stable high educational aspirations and expectations group and the increaser group were equally likely to graduate from high school. High school graduation was positively associated with level of total household income at age 30. Findings suggest that social work efforts that support the development of high educational aspirations and expectations in children may serve to reduce the intergenerational continuity of low-income status.

I-states-as-objects-analysis (ISOA): Extensions of an approach to studying short-term developmental processes by analyzing typical patterns

I-states-as-objects-analysis (ISOA) is a person-oriented methodology for studying short-term developmental stability and change in patterns of variable values. ISOA is based on longitudinal data with the same set of variables measured at all measurement occasions. A key concept is the i-state, defined as a person’s pattern of variable values at a specific time point. All i-states are first subjected to a classification analysis that results in a time-invariant classification characterized by a number of typical i-states. Each person is then characterized at each time point by the typical i-state he/she belongs to. Then the person’s sequences of typical i-states are analyzed with regard to structural and individual stability and change. Extensions of ISOA are presented where: (1) some methods for checking the assumption of a time-invariant classification are indicated; (2) information about the degree of dissimilarity between typical i-states is used as an aid in interpreting the findings; and (3) attention is given to closed paths—that is, typical i-state sequences that do not occur at all. To demonstrate the methods, an empirical example is given that concerns the development of children’s achievement-intelligence patterns between ages 10 and 13.

Treatment response trajectories and antipsychotic medications: examination of up to 18 months of treatment in the CATIE chronic schizophrenia trial

BACKGROUND

Trajectory studies highlight heterogeneity in treatment response, although they are yet to systematically differentiate between antipsychotic medications.

AIMS

To compare treatment response trajectories across antipsychotic medication groups.

METHOD

Data were analyzed from Phase 1 of CATIE, an 18-month double-blind randomized controlled trial of chronic schizophrenia. Change on recurrent Positive and Negative Syndrome Scale (PANSS) administrations for 1124 patients was used to index treatment response trajectories up to 18 months. Trajectory groups were identified with mixed-mode latent class regression modeling. Groups were derived for all participants, and separately for completers, dropouts, and each antipsychotic medication (olanzapine, perphenazine, quetiapine, risperidone, ziprasidone) and then characterized.

RESULTS

Trajectory analysis of the entire sample identified that 18.9% of participants belonged to a group of responders. This figure increased to 31.5% for completers, and fell to 14.5% for dropouts. Olanzapine treated patients were significantly more likely than other treatment groups to belong to the trajectory of responders (n=69, 32.55%; Chi=20.13, df=2, p<.01). Separate trajectory analyses of each medication group showed that all medication groups showed two trajectories except olanzapine that had three trajectories and the only trajectory that attained a 20% PANSS reduction by endpoint.

CONCLUSIONS

Trajectories of treatment response differ between antipsychotic medications and demonstrate substantial heterogeneity in chronic schizophrenia.

The effects of general and alcohol-specific peer factors in adolescence on trajectories of alcohol abuse disorder symptoms from 21 to 33 years

BACKGROUND

The present study examines whether general and alcohol-specific peer risk factors from age 10 to 18 are associated with longitudinal patterns of adult alcohol abuse disorder symptoms from age 21 to 33.

METHODS

Using growth mixture modeling, trajectory groups of alcohol abuse disorder symptoms from age 21 to 33 were identified. We then examined the relationships between the identified trajectory groups of alcohol abuse disorder symptoms and respondents' own adolescent binge drinking, a general negative peer factor, and an alcohol-specific peer factor (having drinking peers) in adolescence using pseudo-class Wald Chi-square tests, and multinomial logistic regressions.

RESULTS

Four different trajectory groups of alcohol abuse disorder symptoms were identified: persistor group (3%), decreaser group (23%), escalator group (3%), and a no-disorder group (71%). Bivariate Wald Chi-square tests indicated that adolescent binge drinking behavior and general and alcohol-specific peer factors differentiated the adult alcohol abuse trajectory groups. Multivariate multinomial logistic regression showed that the general negative peer factors distinguished those who later persisted in alcohol abuse from those who desisted (i.e., persistor group vs. decreaser group) during young adulthood, even after adjusting for respondents' adolescent binge drinking. On the other hand, associating with drinking peers did not distinguish these trajectories.

CONCLUSION

Alcohol-specific peer influences appear to influence alcohol abuse disorder symptoms in the early 20s, while general negative peer exposure in adolescence increases in importance as a risk factor for alcohol abuse disorder symptom persistence in the late 20s and the early 30s.

Trajectories of depressive symptoms and fatigue among postpartum women

OBJECTIVES

To identify and characterize the trajectories of depressive and fatigue symptoms and determine the relationship between these two trajectories and associated predictors.

DESIGN

A prospective, follow-up study.

SETTING

A teaching medical center in central Taiwan.

PARTICIPANTS

A convenience sample of 121 low-risk, childbearing women.

METHODS

Depressive and fatigue symptoms were assessed using the Edinburgh Postnatal Depression Scale and Fatigue Continuum Form respectively during the third trimester (time 1), one day postpartum (time 2), three days postpartum (time 3), and one week postpartum (time 4). Participants also completed structured questionnaires on demographic features, health status, and sleep quality.

RESULTS

The mean age of participants was 31.2 years. We observed four distinctive trajectories of depressive symptoms and three trajectories of fatigue using group-based trajectory modeling. A frequent conoccurrence of similar levels of these symptoms was found; that is, mothers in the high-risk depressive symptoms group were most likely to fall into the high-risk group for fatigue. Joint trajectories were predicted by poor sleep score (odds ratio = 2.96, 95% confidence interval = 1.2, 7.3) using multinomial logistic regression analysis.

CONCLUSION

Overlapping but distinct trajectories of depressive symptoms and fatigue were found. These results suggest that differentiation between depressive symptoms and fatigue is possible and important for improving care during the early postpartum period.

Body mass trajectories through midlife among adults with class I obesity

BACKGROUND

Little is known about the body mass trajectories for adults with class I obesity. Our objective was to map the body mass trajectories through midlife for young adults with class I obesity in the United States.

METHODS

Data from the National Longitudinal Study of Youth 1979 was used to generate a cohort of 1058 men and women, aged 25-33 years with class I obesity in 1990. Group-based trajectory modeling was used to identify the number and shape of the body mass index trajectories from 1990 to 2008 for this cohort.

RESULTS

By 2008, about 15% of men and women with class I obesity in 1990 experienced a body mass index increase to >40 kg/m(2). The trajectory analyses showed that roughly one third of the sample were on 1 of 2 body mass index trajectory groups that culminated with an average BMI well above 35 kg/m(2).

CONCLUSION

The large majority of young adults with class I obesity are likely to gain weight over time. For many, the weight gain will be significant and greatly increase their risk of obesity-related co-morbidities and reduced life expectancy. As a result, bariatric surgery or other intensive weight management options might be warranted.

Individual differences in boys' and girls' timing and tempo of puberty: modeling development with nonlinear growth models

Pubertal development is a nonlinear process progressing from prepubescent beginnings through biological, physical, and psychological changes to full sexual maturity. To tether theoretical concepts of puberty with sophisticated longitudinal, analytical models capable of articulating pubertal development more accurately, we used nonlinear mixed-effects models to describe both the timing and tempo of pubertal development in the sample of 364 White boys and 373 White girls measured across 6 years as part of the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development. Individual differences in timing and tempo were extracted with models of logistic growth. Differential relations emerged for how boys' and girls' timing and tempo of development were related to physical characteristics (body mass index, height, and weight) and psychological outcomes (internalizing problems, externalizing problems, and risky sexual behavior). Timing and tempo are associated in boys but not girls. Pubertal timing and tempo are particularly important for predicting psychological outcomes in girls but only sparsely related to boys' psychological outcomes. Results highlight the importance of considering the nonlinear nature of puberty and expand the repertoire of possibilities for examining important aspects of how and when pubertal processes contribute to development.

Some initial findings and policy implications of the Pathways to Desistance Study

Little is known about how adolescents curtail their offending and make positive adjustments to early adulthood. The Pathways to Desistance study follows 1,354 serious adolescent offenders to provide information about these processes. This paper summarizes some initial findings from the study and lays out their potential policy implications. The findings covered include the variability in the sample, the importance of the link between substance use and offending, and the possible implications of institutional care.

Distinct psychological distress trajectories in rheumatoid arthritis: findings from an inception cohort

OBJECTIVE

As with other chronic physical illness, rates of depressive disorder are high in rheumatoid arthritis (RA). The aim of the current study was to identify distinct trajectories of psychological distress over 10 years in a cohort of RA patients recruited very early in the course of the disease.

METHODS

Psychological distress as measured by the Hospital Anxiety and Depression Scale total score was assessed annually in a subgroup of 784 patients enrolled in a multi-centre RA inception cohort (Early RA Study). A latent growth mixture modelling (GMM) approach was used to identify distinct psychological distress patterns.

RESULTS

Four distinct psychological distress trajectories were observed: low-stable (68%), high-stable (12%), high-decreasing (9%) and low-increasing (11%). Symptoms of pain, stiffness and functional impairment were significantly associated with levels of psychological distress at the time of diagnosis and after 3 years; serological markers of disease activity (ESR and CRP) were not.

CONCLUSIONS

Although the majority of individuals developing RA experience little or no impact of the effects of the disease on their psychological well-being, a significant proportion experience high levels of distress at some point which may be related to their subjective appraisal of their condition. Assessment and treatment of psychological distress should occur synchronously with somatic symptoms.

Dental plaque and oral health during the first 32 years of life

BACKGROUND

Studies investigating the role of dental plaque in oral disease have focused primarily on the quantity and quality of plaque at a given point in time. No large-scale epidemiologic research has been conducted regarding the continuity and change in plaque levels across the long term and the association of plaque levels with oral health.

METHODS

The authors used data from the Dunedin Multidisciplinary Health and Development Study. Collection of dental plaque data occurred at ages 5, 9, 15, 18, 26 and 32 years by means of the Simplified Oral Hygiene Index. The authors assessed oral health outcomes when participants were aged 32 years.

RESULTS

The authors identified three plaque trajectory groups (high, n = 357; medium, n = 450; and low; n = 104) and found substantial, statistically significant differences in both caries and periodontal disease experience among those groups. For example, after the authors controlled for sex, socioeconomic status and dental visiting pattern, they found that participants in the high-plaque-trajectory group lost nearly five times more teeth owing to caries than did those in the low-plaque-trajectory group.

CONCLUSIONS

Across the long term, participants in the high-plaque-trajectory group were more likely to experience caries, periodontal disease and subsequent tooth loss than were those in the low- or medium-plaque-trajectory groups, and they experienced all those conditions with greater severity.

CLINICAL IMPLICATIONS

Improving oral health requires emphasizing long-term self-care, as well as providing broad public health and health promotion measures that promote and support oral self-care. This study's findings suggest that poor oral hygiene and smoking have a synergistic effect on periodontal disease experience.

Role of endothelin-1 in human aneurysmal subarachnoid hemorrhage: associations with vasospasm and delayed cerebral ischemia

BACKGROUND

Endothelin-1 (ET-1) is a potent vasoconstrictor implicated in the pathogenesis of vasospasm and delayed cerebral ischemia (DCI) in aneurysmal subarachnoid hemorrhage (aSAH) patients. The aim of this study was to investigate the relationship between cerebrospinal fluid (CSF) ET-1 levels and angiographic vasospasm and DCI.

METHODS

Patients with aSAH were consented (n = 106). Cerebral vasospasm was determined by angiography. DCI was determined by transcranial Doppler (TCD) results and/or angiogram results with corresponding clinical deterioration. CSF ET-1 levels over 14 days after the initial insult was quantified by ELISA. ET-1 analysis included a group-based trajectory analysis and ET-1 exposure rate during 24, 48, and 72 h prior to, as well as 72 h post angiography, or clinical deterioration.

RESULTS

Trajectory analysis revealed two distinct groups of subjects with 56% of patients in the low ET-1 trajectory group (mean at day 1 = 0.31 pg/ml; SE = 0.04; mean at day 14 = 0.41 pg/ml; SE = 0.15) and 44% of patients in the high ET-1 trajectory group (mean at day 1 = 0.65 pg/ml; SE = 0.08; mean at day 14 = 0.61 pg/ml; SE = 0.06). Furthermore, we observed that ET-1 exposure rate 72 h before angiography and clinical spasm was a significant predictor of both angiographic vasospasm and DCI, whereas, ET-1 exposure after angiography and clinical spasm was not associated with either angiographic vasospasm or DCI.

CONCLUSION

Based on these results we conclude that ET-1 concentrations are elevated in a sub-group of patients and that the acute (72 h prior to angiography and clinical neurological deterioration), but not chronic, elevations in CSF ET-1 concentrations are indicative of the pathogenic alterations of vasospasm and DCI in aSAH patients.

Identifying and characterizing trajectories of cognitive change in older persons with mild cognitive impairment

BACKGROUND

Mild cognitive impairment (MCI) represents a state of high risk for dementia but is heterogeneous in its course. To date, the trajectories reflecting distinct developmental courses of cognition among patients with MCI have not been well defined.

AIM

To identify the developmental trajectory of groups with distinct cognitive change patterns among a cohort of MCI patients.

METHODS

187 MCI patients from 2 geriatric outpatient clinics were evaluated serially with the Mini-Mental State Examination (MMSE) for up to 3.5 years. Group-based trajectory analysis was applied to identify distinct trajectories. Estimates of decline for each group were compared with the mean rate of decline obtained from mixed modeling of the entire sample.

RESULTS

5 trajectories were identified and labeled based on their baseline MMSE score and course: (1) 29/stable (6.5%); (2) 27/stable (53.9%); (3) 25/slow decline (23.8%); (4) 24/slow decline (11.6%); (5) 25/rapid decline (4.2%). Annual rate of change in the MMSE score for these 5 groups was 0.09, -0.43, -1.23, -1.84, and -4.6 points, respectively. None corresponded to the mean rate of -0.82 points estimated for the group as a whole. A majority of MCI patients (60.4%) follow stable cognitive trajectories over time. Within the 3 groups with declining trajectories, cognitive decline occurs slowly in a vast majority of MCI patients (98.5%).

CONCLUSIONS

Results provide direct evidence for the heterogeneous course of cognitive decline that has been suggested by the variable prognosis for patients with MCI.

Spit: Saliva in Nursing Research, Uses and Methodological Considerations in Older Adults

Over the last 10 years, interest in the analysis of saliva as a biomarker for a variety of systemic diseases or for potential disease has soared. There are numerous advantages to using saliva as a biological fluid, particularly for nurse researchers working with vulnerable populations, such as frail older adults. Most notably, it is noninvasive and easier to collect than serum or urine. The authors describe their experiences with the use of saliva in research with older adults that examined (a) osmolality as an indicator of hydration status and (b) cortisol and behavioral symptoms of dementia. In particular, the authors discuss the timing of data collection along with data analysis and interpretation. For example, it is not enough to detect levels or rely solely on summary statistics; rather it is critical to characterize any rhythmicity inherent in the parameter of interest. Not accounting for rhythmicity in the analysis and interpretation of data can limit the interpretation of associations, thus impeding advances related to the contribution that an altered rhythm may make to individual vulnerability.

Change trajectories during home-based services with chronic child welfare cases

This study examines how risk factor change patterns vary with case chronicity, and whether risk factor improvement still predicts lower recidivism risk among chronic cases. 2,175 parents in home based child welfare services were surveyed for risk factors at pre-treatment, post-treatment and 6-month follow-up. Mixture modeling of latent difference scores identified change trajectory classes related retrospectively to chronicity and prospectively to recidivism. Five change trajectories were identified: stable low problem, stable high problem, sustained improvement, relapsing, and paradoxical. Chronicity was associated with a decreasing probability of membership in the stable low problem trajectory and increasing probability of membership in the stable high problem and sustained improvement trajectories. Cases with more favorable trajectories recidivated less across levels of chronicity. Findings suggest that chronic cases may improve little, but still retain a stable or increasing chance of sustained improvement associated with lower risk. A cumulative service benefit might be one possible explanation for this observation, and might suggest that repeated intervention efforts are not always wasted on chronic cases. The current episodic and reactive service delivery model in child welfare may be a mismatch with chronic cases where progress is absent or tends to occur cumulatively across service episodes.

Patterns of nonadherence to antiepileptic drug therapy in children with newly diagnosed epilepsy

CONTEXT

Because of epilepsy's common occurrence, the narrow therapeutic and safety margins of antiepileptic medications, and the recognized complications of medication nonadherence in adults with epilepsy, identifying the rates, patterns, and predictors of nonadherence in children with epilepsy is imperative. The onset and evolution of antiepileptic drug nonadherence in children with newly diagnosed epilepsy remains unknown.

OBJECTIVES

To identify and characterize trajectories of adherence in children with newly diagnosed epilepsy over the first 6 months of therapy and to determine sociodemographic and epilepsy-specific predictors of adherence trajectories.

DESIGN, SETTING, AND PATIENTS

Prospective, longitudinal observational study of antiepileptic drug adherence in a consecutive cohort of 124 children (2-12 years old) with newly diagnosed epilepsy at Cincinnati Children's Hospital Medical Center. Patients were recruited from April 2006 through March 2009, and final data collection occurred in September 2009.

MAIN OUTCOME MEASURE

Objective adherence measured using electronic monitors.

RESULTS

Fifty-eight percent of children with newly diagnosed epilepsy demonstrated persistent nonadherence during the first 6 months of therapy. Group-based trajectory models identified 5 differential adherence patterns (Bayesian information criterion = -23611.8): severe early nonadherence (13%; 95% confidence interval [CI], 8%-20%), severe delayed nonadherence (7%; 95% CI, 3%-12%), moderate nonadherence (13%; 95% CI, 8%-20%), mild nonadherence (26%; 95% CI, 19%-34%), and near-perfect adherence (42%; 95% CI, 33%-50%). The adherence pattern of most patients was established by the first month of therapy. Socioeconomic status was the sole predictor of adherence trajectory group status (χ(4)(2) = 19.3 [n = 115]; P < .001; partial r(2) = 0.25), with lower socioeconomic status associated with higher nonadherence.

CONCLUSION

Five trajectory patterns were identified that captured the spectrum of nonadherence to antiepileptic drugs among children with newly diagnosed epilepsy; the patterns were significantly associated with socioeconomic status.