ABSTRACT
Purpose: The study was designed to evaluate whether an educational intervention to train the health center (HC) staff to optimize care for sexual and gender minority (SGM) patients could improve documentation of sexual orientation and gender identity (SOGI) and increase preventive screenings. Methods: Twelve HCs were matched and randomized to either receive a tailored, multicomponent educational intervention or a 1-hour prerecorded webinar. Documentation of SGM status and clinical testing was measured through analysis of data that HCs report annually. Nonparametric statistics were used to assess associations between baseline HC characteristics and outcome measures. Results: The HCs were geographically, racially, and ethnically diverse. In all but one HC, <10% of the patients were identified as SGM. Intervention HCs underwent between 3 and 10 trainings, which were highly acceptable. In 2018, 9 of 12 HCs documented SO and 11 of 12 documented GI for at least 50% of their patients. Five of 6 intervention HCs increased SO documentation by 2020, compared to 3 of 6 control HCs (nonsignificant, NS). Five intervention HCs increased GI documentation, although generally by less than 10%, compared to 2 of the controls (NS). Intervention HCs tended to increase documentation of preventive services more than control HCs, but the changes were NS. Conclusions: An educational intervention designed to train the HC staff to provide culturally responsive services for SGM patients was found to be acceptable, with favorable, but nonsignificant changes. Further refinement of the intervention using a larger sample of HCs might demonstrate the effectiveness of this approach. Clinical trial registration #: NCT03554785.
Subject(s)
Gender Identity , Sexual and Gender Minorities , Humans , Female , Male , Sexual BehaviorABSTRACT
Parents of children with autism spectrum disorder (ASD) and other chronic health conditions often face exceptional caregiving demands that can lead to challenges related to maintaining and succeeding in employment. Detailed information on the specific ways in which these health conditions impact parent employment could aid in designing equitable, effective policies to support families. The r-Kids study used electronic health records to identify three groups of children: those with ASD, asthma, or neither condition (control), from several health care systems. We oversampled racial and ethnic minorities and matched the asthma and control groups to the age and sex distribution of the ASD group. Parents completed three online surveys over the course of a year to measure annual employment outcomes. Surveys included the Family Economic Impact Inventory (measuring employment impacts) and measures of quality of life and symptom severity. All materials were provided in English and Spanish. The study enrolled 1461 families (564 ASD, 468 asthma, 429 control). Youth were 3-16.5 years old and predominantly male (79%). The sample was diverse (43% non-Hispanic White; 35% non-Hispanic Asian, Black, Native Hawaiian, or Other; and 21% Hispanic ethnicity). Parents of children with ASD were significantly less likely to be employed than parents of youth with asthma and control combined (OR: 14.2, p < 0.001), and were more likely to have other difficulties with employment and productivity while at work. Public and employer policies to help mitigate these impacts could aid families in managing care for youth with ASD.
Subject(s)
Asthma , Autism Spectrum Disorder , Child , Adolescent , Humans , Male , Child, Preschool , Female , Autism Spectrum Disorder/diagnosis , Quality of Life , Parents , EmploymentABSTRACT
OBJECTIVE: Trauma exposure is widely prevalent, with more than 60% of adolescents having experienced at least 1 traumatic event and a third of those at high risk to develop posttraumatic stress disorder (PTSD). Data are scarce and out of date on the services children and adolescents with PTSD receive, impeding efforts to improve care and outcomes. This study examines health service use for a large and diverse sample of children and adolescents with and without a diagnosis of PTSD. METHOD: Using a matched case-control study, we gathered information from 4 large health care systems participating in the Mental Health Research Network. Data from each site's electronic medical records on diagnoses, health care encounters, and demographics were analyzed. Nine hundred fifty-five 4- to 18-year-olds with a diagnosis of PTSD were identified and matched on a 1:5 ratio to 4770 controls. We compared cases with controls on frequency of service use in outpatient primary care, medical specialty care, acute care, and mental health care. We also assessed psychotropic medication use. RESULTS: Children and adolescents diagnosed with PTSD used nearly all physical and mental health service categories at a higher rate than controls. However, one-third of children and adolescents did not receive even 1 outpatient mental health visit (36.86%) during the year-long sampling window. CONCLUSION: Our findings suggest that children and adolescents diagnosed with PTSD may have unmet mental health needs. They are high utilizers of health services overall, but lower utilizers of the sectors that may be most helpful in resolving their symptoms.
Subject(s)
Mental Health Services , Stress Disorders, Post-Traumatic , Adolescent , Case-Control Studies , Child , Humans , Mental Health , Outpatients , Stress Disorders, Post-Traumatic/diagnosis , Stress Disorders, Post-Traumatic/epidemiology , Stress Disorders, Post-Traumatic/therapyABSTRACT
BACKGROUND: There is currently little research describing patient experience and continuity of care immediately prior, during, and following an acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This analysis examined clinical characteristics, chronic obstructive pulmonary disease (COPD)related medication patterns and outpatient visits before and after an AECOPD. METHODS: This retrospective analysis used electronic health records, medical claims, and pharmacy dispensing data for patients within the Kaiser Permanente Northwest Health System. Patients with ≥1 AECOPD between January 1, 2015 and December 31, 2017 were identified. The most recent AECOPD was considered the index date. An AECOPD was defined as an inpatient hospitalization with a primary diagnosis of COPD, or respiratory failure with a secondary diagnosis of COPD, or an outpatient visit with a primary diagnosis of COPD and dispensing of respiratory-related antibiotics and/or oral corticosteroids ±5 days of the visit. Eligible patients were: ≥40 years old; ≥2 encounters within 12 months of each other or ≥1 hospitalization with primary or secondary COPD diagnosis, chronic bronchitis, or emphysema prior to index; and continuously enrolled ±90 days relative to index. COPD-related inhaled maintenance medication, rescue inhalers, oral corticosteroid use, and ambulatory visits were assessed 90-days pre- and post-index. RESULTS: There were 2829 patients included (mean [standard deviation] age: 69.0 [10.5] years) who had an AECOPD (7% severe; 93% moderate). The percentage of patients on inhaled maintenance therapy increased from 60.6% pre-AECOPD to 68.8% post-AECOPD and increased from 60.0% to 87.4% among patients who experienced a severe AECOPD. COPD-related ambulatory visits increased more than four-fold for primary care and more than doubled for pulmonologist visits in the post-AECOPD period. CONCLUSION: The low proportion of patients observed with changes to controller and rescue medication (particularly following a moderate AECOPD), yet higher utilization of COPD-related ambulatory visits before and after an AECOPD suggests that there is opportunity to improve pharmacotherapy management.
Subject(s)
Bronchitis, Chronic , Delivery of Health Care, Integrated , Pulmonary Disease, Chronic Obstructive , Adult , Aged , Continuity of Patient Care , Disease Progression , Humans , Pulmonary Disease, Chronic Obstructive/diagnosis , Pulmonary Disease, Chronic Obstructive/drug therapy , Retrospective StudiesABSTRACT
Childhood obesity has increased significantly in the United States. Racial subgroups are often grouped into categories in research, limiting our understanding of disparities. This study describes the prevalence of obesity among youth of diverse racial and ethnic backgrounds receiving care at community health centers (CHCs). This cross-sectional study describes the prevalence of elevated body mass index (BMI) (≥85th percentile) and obesity (≥95th percentile) in youth aged 9 to 19 years receiving care in CHCs in 2014. Multilevel logistic regression estimated the prevalence of elevated BMI and obesity by age, race/ethnicity, and sex. Among 64 925 youth, 40% had elevated BMI and 22% were obese. By race, obesity was lowest in the combined Asian/Pacific Islander category (13%); however, when subgroups were separated, the highest prevalence was among Native Hawaiians (33%) and Other Pacific Islanders (42%) and the lowest in Asians. By sex, Black females and Hispanic and Asian males were more likely to be obese. By age, the highest prevalence of obesity was among those aged 9 to 10 years (25%). Youth served by CHCs have a high prevalence of obesity, with significant differences observed by race, sex, and age. Combining race categories obscures disparities. The heterogeneity of communities warrants research that describes different populations to address obesity.
Subject(s)
Body Mass Index , Community Health Centers , Pediatric Obesity , Adolescent , Adult , Child , Community Health Centers/statistics & numerical data , Cross-Sectional Studies , Ethnicity/statistics & numerical data , Female , Humans , Male , Pediatric Obesity/epidemiology , Pediatric Obesity/ethnology , Prevalence , United States/epidemiology , Young AdultABSTRACT
BACKGROUND: Multiple morbidity is the norm in advanced COPD and contributes to high symptom burden and worse outcomes. RESEARCH QUESTION: Can distinct comorbidity profiles be identified and validated in a community-based sample of patients with COPD from a large integrated health care system using a standard, commonly used diagnostic code-based comorbidity index and downstream 2-year health care use data? STUDY DESIGN AND METHODS: In this retrospective cohort study, we used latent class analysis (LCA) to identify comorbidity profiles in a population-based sample of 91,453 patients with a COPD diagnosis between 2011 and 2015. We included specific comorbid conditions from the Charlson Comorbidity Index (CCI) and accounted for variation in underlying prevalence of different comorbidities across the three study sites. Sociodemographic, clinical, and health-care use data were obtained from electronic health records (EHRs). Multivariate logistic regression analysis was used to compare rates of acute and postacute care use by class. RESULTS: The mean age was 71 ± 11 years, 55% of patients were women, 23% of patients were people of color, and 80% of patients were former or current smokers. LCA identified four distinct comorbidity profiles with progressively higher CCI scores: low morbidity (61%; 1.9 ± 1.4), metabolic renal (21%; 4.7 ± 1.8), cardiovascular (12%; 4.6 ± 1.9), and multimorbidity (7%; 7.5 ± 1.7). In multivariate models, during 2 years of follow-up, a significant, nonoverlapping increase was found in the odds of having any all-cause acute (hospitalizations, observation stays, and ED visits) and postacute care use across the comorbidity profiles. INTERPRETATION: Distinct comorbidity profiles can be identified in patients with COPD using standard EHR-based diagnostic codes, and these profiles are associated with subsequent acute and postacute care use. Population-based risk stratification schemes for end-to-end, comprehensive COPD management should consider integrating comorbidity profiles such as those found in this study.
Subject(s)
Delivery of Health Care, Integrated/standards , Electronic Health Records/statistics & numerical data , Pulmonary Disease, Chronic Obstructive/epidemiology , Subacute Care/statistics & numerical data , Terminal Care/standards , Aged , Comorbidity , Female , Follow-Up Studies , Humans , Male , Pulmonary Disease, Chronic Obstructive/therapy , Retrospective Studies , Time Factors , United States/epidemiologyABSTRACT
OBJECTIVE: To assess the impact of provider incentive policy on smoking status documentation. DATA SOURCES: Primary data were extracted from structured electronic medical records (EMRs) from 15 community health centers (CHCs). STUDY DESIGN: This was an observational study of data from 2006 to 2013, assessing changes in documentation of smoking status over time. DATA EXTRACTION METHODS: We extracted structured EMR data for patients age 18 and older with at least one primary care visit. PRINCIPAL FINDINGS: Rates of documented smoking status rose from 30 percent in 2006 to 90 percent in 2013; the largest increase occurred from 2011 to 2012 following policy changes (21.3% [95% CI, 8.2%, 34.4%] from the overall trend). Rates varied by clinic and across patient subgroups. CONCLUSIONS: Documentation of smoking status improved markedly after introduction of new federal standards. Further improvement in documentation is still needed, especially for males, nonwhite patients, those using opioids, and HIV + patients. More research is needed to study whether changes in documentation lead to improvements in counseling, cessation, and patient outcomes.
Subject(s)
Community Health Centers/statistics & numerical data , Documentation/statistics & numerical data , Health Policy , Safety-net Providers/legislation & jurisprudence , Safety-net Providers/statistics & numerical data , Smoking/epidemiology , Smoking/trends , Adolescent , Adult , Aged , Aged, 80 and over , Female , Forecasting , Humans , Male , Medicare/legislation & jurisprudence , Medicare/statistics & numerical data , Middle Aged , United States , Young AdultABSTRACT
OBJECTIVE: This study examines the impact of the transition from ICD-9-CM to ICD-10-CM diagnosis coding on the recording of mental health disorders in electronic health records (EHRs) and claims data in ten large health systems. We present rates of these diagnoses across two years spanning the October 2015 transition. METHODS: Mental health diagnoses were identified from claims and EHR data at ten health care systems in the Mental Health Research Network (MHRN). Corresponding ICD-9-CM and ICD-10-CM codes were compiled and monthly rates of people receiving these diagnoses were calculated for one year before and after the coding transition. RESULTS: For seven of eight diagnostic categories, monthly rates were comparable during the year before and the year after the ICD-10-CM transition. In the remaining category, psychosis excluding schizophrenia spectrum disorders, aggregate monthly rates of decreased markedly with the ICD-10-CM transition, from 48 to 33 per 100,000. We propose that the change is due to features of General Equivalence Mappings (GEMS) embedded in the EHR. CONCLUSIONS: For most mental health conditions, the transition to ICD-10-CM appears to have had minimal impact. The decrease seen for psychosis diagnoses in these health systems is likely due to changes associated with EHR implementation of ICD-10-CM coding rather than an actual change in disease prevalence. It is important to consider the impact of the ICD-10-CM transition for all diagnostic criteria used in research studies, quality measurement, and financial analysis during this interval.
ABSTRACT
OBJECTIVES: As the life expectancy of people infected with human immunodeficiency virus (HIV) infection has increased, the spectrum of illness has evolved. We evaluated whether people living with HIV accessing primary care in US community health centers had higher morbidity compared with HIV-uninfected patients receiving care at the same sites. METHODS: We compared data from electronic health records for 12 837 HIV-infected and 227 012 HIV-uninfected patients to evaluate the relative prevalence of diabetes mellitus, hypertension, chronic kidney disease, dyslipidemia, and malignancies by HIV serostatus. We used multivariable logistic regression to evaluate differences. Participants were patients aged ≥18 who were followed for ≥3 years (from January 2006 to December 2016) in 1 of 17 community health centers belonging to the Community Health Applied Research Network. RESULTS: Nearly two-thirds of HIV-infected and HIV-uninfected patients lived in poverty. Compared with HIV-uninfected patients, HIV-infected patients were significantly more likely to be diagnosed and/or treated for diabetes (odds ratio [OR] = 1.18; 95% confidence interval [CI], 1.22-1.41), hypertension (OR = 1.38; 95% CI, 1.31-1.46), dyslipidemia (OR = 2.30; 95% CI, 2.17-2.43), chronic kidney disease (OR = 4.75; 95% CI, 4.23-5.34), lymphomas (OR = 4.02; 95% CI, 2.86-5.67), cancers related to human papillomavirus (OR = 5.05; 95% CI, 3.77-6.78), or other cancers (OR = 1.25; 95% CI, 1.10-1.42). The prevalence of stroke was higher among HIV-infected patients (OR = 1.32; 95% CI, 1.06-1.63) than among HIV-uninfected patients, but the prevalence of myocardial infarction or coronary artery disease did not differ between the 2 groups. CONCLUSIONS: As HIV-infected patients live longer, the increasing burden of noncommunicable diseases may complicate their clinical management, requiring primary care providers to be trained in chronic disease management for this population.
Subject(s)
Community Health Centers/statistics & numerical data , HIV Infections/epidemiology , Adolescent , Adult , Aged , Diabetes Mellitus/epidemiology , Dyslipidemias/epidemiology , Electronic Health Records , Female , Humans , Hypertension/epidemiology , Male , Middle Aged , Neoplasms/epidemiology , Prevalence , Renal Insufficiency, Chronic/epidemiology , Socioeconomic Factors , Young AdultABSTRACT
BACKGROUND: Little is known about statin underutilization among diabetes mellitus patients cared for in community health centers, which tend to serve socioeconomically disadvantaged populations. Implications of the American College of Cardiology/American Heart Association (ACC/AHA) guidelines on preexisting gaps in statin treatment in this population are unclear. METHODS AND RESULTS: We included 32 440 adults (45% male, 63% nonwhite, 29% uninsured/Medicaid) aged 40 to 75 years with diabetes mellitus who received care within 16 community health center groups in 11 states in the Community Health Applied Research Network during 2013. Statin prescribing was analyzed as a function of concordance with the National Cholesterol Education Program Adult Treatment Panel 2001 and ACC/AHA 2013 guidelines. More patients' treatments were concordant with the ACC/AHA (52.8%) versus the National Cholesterol Education Program Adult Treatment Panel (36.2%) guideline. Female sex was associated with lower concordance for both (odds ratio [OR] 0.90, CI 0.85-0.94; and OR 0.84, CI 0.80-0.88, respectively). Being insured, an Asian/Pacific Islander, or primarily Spanish speaking were associated with greater concordance for both guidelines: 35.5% (11 526/32 440) were concordant with neither guideline, the majority (79.7%) having no statin prescribed; 28.2% (9168/32 440) were concordant with ACC/AHA but not the National Cholesterol Education Program Adult Treatment Panel. 8.7% of these patients had a low-density lipoprotein cholesterol >160 mg/dL despite having a moderate- or high-intensity statin prescribed. And 11.6% (3772/32 440) were concordant with the National Cholesterol Education Program Adult Treatment Panel but not with ACC/AHA. Most of these patients had a low-density lipoprotein cholesterol between 70 and 99 mg/dL with no or a low-intensity statin prescribed. CONCLUSIONS: Opportunities exist to improve cholesterol management in diabetes mellitus patients in community health centers. Addressing care gaps could improve cardiovascular disease prevention in this high-risk population.
Subject(s)
American Heart Association , Cardiovascular Diseases/prevention & control , Cholesterol/blood , Community Health Centers/standards , Diabetes Mellitus/therapy , Dyslipidemias/drug therapy , Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Practice Guidelines as Topic/standards , Practice Patterns, Physicians'/standards , Primary Prevention/standards , Adult , Aged , Biomarkers/blood , Cardiovascular Diseases/diagnosis , Cardiovascular Diseases/ethnology , Cross-Sectional Studies , Diabetes Mellitus/diagnosis , Diabetes Mellitus/ethnology , Drug Utilization Review , Dyslipidemias/blood , Dyslipidemias/diagnosis , Dyslipidemias/ethnology , Electronic Health Records , Female , Guideline Adherence/standards , Humans , Linear Models , Logistic Models , Male , Middle Aged , Multivariate Analysis , Odds Ratio , Quality Improvement/standards , Quality Indicators, Health Care/standards , Risk Assessment , Risk Factors , Time Factors , Treatment Outcome , United States/epidemiologyABSTRACT
INTRODUCTION: Autism spectrum disorders (ASD) are lifelong neurodevelopmental disorders, and little is known about how parents address the health and psychosocial consequences of ASD. Few studies have examined use of various treatments and services in a large, diverse sample of children with ASD and their families. OBJECTIVE: This paper presents methods to create an autism research resource across multiple large health delivery systems and describes services and treatments used by children with ASD and their families. METHODS: Four study sites conducted a Web survey of parents of children and adolescents with ASD who were members of Kaiser Permanente. We tabulated data distributions of survey responses and calculated χ2 statistics for differences between responders and nonresponders. RESULTS: The children of the 1155 respondents were racially and ethnically diverse (55% white, 6% black, 5% Asian, 9% multiracial, 24% Hispanic) and representative of the total population invited to participate with respect to child sex (83% male), child age (57% < 10 years), and ASD diagnosis (64% autistic disorder). The most frequently used services and treatments were Individualized Education Programs (85%), family physician visits (78%), and occupational and speech therapy (55% and 60%, respectively). Home-based programs frequently included implementation of social skills training (44%) and behavior management (42%). Prescription medication use was high (48%). Caregivers reported disruption of personal and family routines because of problem behaviors. CONCLUSION: These survey data help to elucidate parents' experiences with health services for their children with ASD and serve as a potential resource for future research.
Subject(s)
Autism Spectrum Disorder/therapy , Health Care Surveys/statistics & numerical data , Mental Health Services/statistics & numerical data , Parents , Adolescent , Child , Child, Preschool , Female , Health Care Surveys/methods , Humans , Infant , MaleABSTRACT
This study examines medical conditions diagnosed prior to the diagnosis of autism spectrum disorder (ASD). Using a matched case control design with 3911 ASD cases and 38,609 controls, we found that 38 out of 79 medical conditions were associated with increased ASD risk. Developmental delay, mental health, and neurology conditions had the strongest associations (ORs 2.0-23.3). Moderately strong associations were observed for nutrition, genetic, ear nose and throat, and sleep conditions (ORs 2.1-3.2). Using machine learning methods, we clustered children based on their medical conditions prior to ASD diagnosis and demonstrated ASD risk stratification. Our findings provide new evidence indicating that children with ASD have a disproportionate burden of certain medical conditions preceding ASD diagnosis.
Subject(s)
Autism Spectrum Disorder/epidemiology , Child Health/statistics & numerical data , Developmental Disabilities/epidemiology , Case-Control Studies , Child , Child, Preschool , Female , Humans , Male , Mental Health/statistics & numerical data , RiskABSTRACT
BACKGROUND: The Affordable Care Act increases access to treatment services for people who suffer from substance use disorders (SUDs), including alcohol use disorders (AUDs) and opioid use disorders (OUDs). This increased access to treatment has broad implications for delivering health services and creates a dramatic need for transformation in clinical care, service lines, and collaborative care models. Medication-assisted treatments (MAT) are effective for helping SUD patients reach better outcomes. This article uses electronic health record (EHR) data to examine the prevalence of EHR-documented SUDs, patient characteristics, and patterns of MAT prescribing and screening for patients within the Community Health Applied Research Network (CHARN), a national network of 17 community health centers that facilitates patient-centered outcomes research among underserved populations. METHODS: Hierarchical generalized linear models examined patient characteristics, SUD occurrence rates, MAT prescription, and human immunodeficiency virus (HIV) and hepatitis virus C screening for patients with AUDs or OUDs. Results: Among 572,582 CHARN adult patients, 16,947 (3.0%) had a documented AUD diagnosis and 6,080 (1.1%) an OUD diagnosis. Alcohol MAT prescriptions were documented for 547 AUD patients (3.2%) and opioid MAT for 1,764 OUD patients (29.0%). Among OUD patients, opioid MAT was significantly associated with HIV screening (odds ratio [OR] = 1.31, P < .001) in OUD patients, as was alcohol MAT among AUD patients (OR = 1.30, P = .013). CONCLUSIONS: These findings suggest that effective opioid and alcohol MAT may be substantially underprescribed among safety-net patients identified as having OUDs or AUDs.
Subject(s)
Community Health Centers/statistics & numerical data , Drug Utilization/statistics & numerical data , Electronic Health Records/statistics & numerical data , Practice Patterns, Physicians'/statistics & numerical data , Substance-Related Disorders/epidemiology , Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Substance-Related Disorders/drug therapy , United States/epidemiology , Young AdultABSTRACT
Using data from multiple health systems (2009-2010) and the largest sample to date, this study compares health services use among youth with and without an autism spectrum disorder (ASD)-including preventive services not previously studied. To examine these differences, we estimated logistic and count data models, controlling for demographic characteristics, comorbid physical health, and mental health conditions. Results indicated that youth with an ASD had greater health care use in many categories, but were less likely to receive important preventive services including flu shots and other vaccinations. An improved understanding of the overall patterns of health care use among this population could enable health systems to facilitate the receipt of appropriate and effective health care.
Subject(s)
Autism Spectrum Disorder/psychology , Mental Health Services/statistics & numerical data , Patient Acceptance of Health Care/psychology , Patient Acceptance of Health Care/statistics & numerical data , Preventive Health Services/statistics & numerical data , Primary Health Care/statistics & numerical data , Adolescent , Age Factors , Case-Control Studies , Child , Child, Preschool , Emergency Medical Services/statistics & numerical data , Female , Humans , Male , United StatesABSTRACT
To identify factors associated with valid Autism Spectrum Disorder (ASD) diagnoses from electronic sources in large healthcare systems. We examined 1,272 charts from ASD diagnosed youth <18 years old. Expert reviewers classified diagnoses as confirmed, probable, possible, ruled out, or not enough information. A total of 845 were classified with 81% as a confirmed, probable, or possible ASD diagnosis. The predictors of valid ASD diagnoses were >2 diagnoses in the medical record (OR 2.94; 95% CI 2.03-4.25; p < 0.001) and being male (OR 1.51; 95% CI 1.05-2.17; p = 0.03). In large integrated healthcare settings, at least two diagnoses can be used to identify ASD patients for population-based research.
Subject(s)
Autism Spectrum Disorder/diagnosis , Delivery of Health Care/methods , Electronic Health Records , Adolescent , Delivery of Health Care/standards , Female , Humans , Male , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
We examined the effect of reproductive and life history strategies on the amount and partitioning of genetic variation in three annual species of Nuttallanthus. The North American species N. canadensis, N. floridanus, and N. texanus have regional to widespread ranges that overlap in the southeastern USA, are characterized by homogeneous populations and high fecundity, and possess showy, fragrant flowers seemingly adapted for insect pollination and outbreeding. Field and greenhouse studies on plants from 25 populations indicated that reproductive strategies were similar among species and showed predominant self-fertilization via cleistogamy and self-pollination prior to anthesis in chasmogamous flowers. Species were reproductively isolated and demonstrated complete cross-incompatibility after experimental crosses and no evidence for hybridization in mixed populations. Genetic variation was assessed using starch gel electrophoresis to resolve 15 isozyme loci in 50 populations. Conspecific genetic identity (I) values were high (0.819-0.936), but interspecific comparisons indicated many qualitative allelic differences and correspondingly low I values (0.516-0.623). Low levels of polymorphism and observed heterozygosity within populations and the disproportionate amount of gene diversity distributed among populations were concordant with reproductive data. The pattern of genetic differentiation was most similar to that observed in species with a predominantly inbreeding mating system.