Epidemiological studies investigate the rate at which diseases aremanifested among different cohorts of people and more so why observedoutcomes occur. Epidemiological data is applied in the planning andevaluation of strategies aimed at disease prevention as well as beingapplied as guides towards the appropriate management of patientgroups in whom the disease in question is developing (Twisk, 2013). Alongitudinal epidemiological study is aimed at tracing forward theevaluation of effects of one or more disease development variablesover a given period.
In their study,Stotmeyer et al. (2010) describes the long-term retention among olderadults in the study of vascular health. As such, the scientistsconducted the longitudinal epidemiological research to defineretention i.e. holding surviving partakers registered at baseline forensuing evaluations in a longitudinal cohort study, according to ageand visit type. The study also sought to define physiognomiesassociated with different visit types (i.e. home, clinic, andtelephone) for longitudinal study in older participants. In thisregards, the assessment of the article concerning epidemiological,research design, framework, and the statistical tests is significantin providing a rationale for cardiovascular diseases.
The researchershave set the research problem in the introduction section of thepaper in paragraph one and two. The study’s statement encompassestwo sections i.e. retention according to age and visit type, andcharacteristics associated with visit types thus, a complex researchproblem. As such, the research problem takes the form of adescriptive element rather than an assertion. In paragraph one, theauthors describe the research problem and then follow in paragraphtwo with an explanation of the described research problem. In thisregards, the study’s research problem is defined as, skewedretention is related to depressive symptoms among older adults thus,attendance is a significant risk factor. As such, the researcherscarried out a study on 5,888 participants aged 65 to 100 tounderstand the effect of retention and the features associated withvisit types.
On the other hand, the study has a clear statement of purpose.Introducing the topic, the authors contend that the aged are crucialto study concerning risk incidences and health outcomes. Furthermore,the article provides a reference i.e. cohort studies on attendanceespecially among the aged. In addition, the article describes thesetting of the research i.e. 4 U.S. clinical sites, the design of thestudy i.e. a longitudinal cohort study, the research objective andpurpose i.e. to study whether older age is connected with recurringclinical visit and the ensuing visit types in the CHS. To demonstratethe simplicity of the statement, the authors have defined anddescribed the main concepts that shape the study such as retention,CHS, and visit types. On the other hand, although the study has notexplicitly stated a research question, it has described the questionwithin the precepts of the research problem and statement thus, thequestion is not well stated. As such, the question is integratedwithin the problem and the research objective i.e. whether age isassociated with recurring visits and whether there any variationsbetween age and other factors.
The study reports a complex and a non-directional hypothesis.Furthermore, the researchers tested the reported hypothesis. Thehypothesis is non-directional since the authors do not stipulate thedirection, previous research on retention has not been published, andthe research contains impartiality. On the other hand, the hypothesisis complex since it contains several variables i.e. relation betweenvisit type and health, lifestyle, demography, and characteristics. Inaddition, the study relates age and retention thus, the existingimpartiality and multiple variables point to a non-directional andcomplex hypothesis. The study tested the hypothesis through a cohortstudy. In the conclusion, the authors assert that older adults have ahigh likelihood of missing visits, but high phone and home visits incomparison to other groups.
Stotmeyer et al. (2010) study is an observational procedure wherethey observed the risk factors, clinic visits, and retentionassociated with older adults. As such, the study used assessments andquestionnaires in evaluating the variables. In fact, the research isretrospective and the researchers have not attempted to influence theoutcome of the procedure since the study cultivated an assessment andan observational criterion only. In addition, the study was alongitudinal cohort study i.e. the researchers followed one group andrelated the group to another group. On the other hand, theresearchers used an appropriate research design i.e. a longitudinalcohort study. Since, the study involved observing and assessingcharacteristics associated with visit types, there did not exist anyother worth design. In fact, the study was retrospective i.e.followed the cohort group for a period, before analyzing the study.
Stotmeyer et al. (2010) used a significance level of type one error.Before undertaking the study, they established a tolerance forcommitting the error (i.e. P<.001), which correlated withthe 5% of rejecting a null hypothesis incorrectly. In this regards,the sample size proved significant in defining the power. As such,the power is highly significant in studies as it define whether aresearch has a good likelihood of generating a statisticallynoteworthy outcome if a variance actually exists in the population.In this regards, the power cultivates the performance of anaccountable research.
Long-term retention of older adults in the Cardiovascular HealthStudy (CHS): Implications for studies of the oldest old is an articlepublished in the Journal of the American Geriatrics Society based ona longitudinal epidemiological study.Stotmeyer et al. (2010)published this article to present findings from a longitudinal cohortstudy describing retention relative to visit type and age and more sodetermine common characteristics featured relative to visit typeamong older adults participating in the epidemiological study.
The study involved participants from a credible source, theCardiovascular Health Study cohort. This study center approved thestudy thus informing participants of the intention of the study andgetting their approval in line with ethical credibility required ofresearch studies. The sample size included 5,201 participants with amean age of 73 for the 65 to 100 years age group, which includednearly all ethnic groups of the American society, as well as anadditional 687 participants from the African American demographicgroup (Stotmeyer et al. 2010). The participants were sourced fromfour CHS centers representing Forsyth County, North CarolinaSacramento County, California Washington County, Maryland andAllegheny County and Pennsylvania. This justifies the inference thatfindings are indeed true.
The sampling criteria involved cohorts from 1989 to 1990, an AfricanAmerican cohort from 1992 to 1993. These sample sizes were evaluatedin according to standardized clinical procedures, lab assessments,physical and cognitive functioning examinations as well as individualparticipant’s medical history. These components were consistentlyexamined during annual clinic visits through to 198 to 1999.Surviving participants who continued with the annual clinical visitsnumbering 43,772 improved the sample criteria (Stotmeyer et al.2010). For the 2005 to 2006 sample size, all surviving CHS cohortswere recruited once again for cognitive and physical assessmentreexaminations in an effort to reaffirm the functional status of thesample criteria. At this point, the median age was 85 and the samplesize ranged from 77 to 102 years. Over 60% of the sample participantswere female while nearly 17 % was from the African American crosssection of the American population (Stotmeyer et al. 2010).
Yearly visit types for the decade spanning 1989 to 1999 includedtelephone correspondence, home visits and other forms such asself-completed clinical re-evaluation forms as well as nursing homevisits. From 2005 to 2006, clinic and home visits exhibitedidentical in- person physiological assessment and questionnaireresults as opposed to previous years where home visits wereabbreviated (Stotmeyer et al. 2010). The health assessments involvedincluded medical factors such as medical history, medication andhospitalization trends psychosocial factors such as health anddepression attributes: blood pressure, physical functioning andfitness cognitive functioning as well as lab assays similar to thoseadhered to in previous participant assessments. For the assessment ofdemographic and lifestyle factors, smoking trends, weight factors,education and self-reported health results were collected throughquestionnaires.
The statistical data and tests utilized duringthe procedure were appropriate and the statistical tests applied inthe study included multivariable analysis and chi-square tests forthe assessments of participants characteristics for clinic visits in1998 to 1999 and for 2005 to 2006 in comparison to visit typesaddressed in 2005 to 2006 (Stotmeyer et al. 2010). The comparison ofpairs was adjusted using the Bonferroni correction for multipleevaluations. Multinomial logistic regression was applied in studyingvisit type used in 2005 to 2006 in accordance to characteristicsrealized in 1998 to 1999 where telephone correspondence was used asthe reference group. These statistical tests provided results, whichclosely related to the objectives of the study. In fact, the testsas aforementioned indicate the hypothesized information as the testsused were appropriate and reflected the population values as sought(i.e. N=43,772 for annual contacts during 1999 and a median age of 73years and N= 1942 for 2005-2006 and a median age of 85 years).
The inferences made in this study are indeed relevant as they areaccurate. The longitudinal epidemiological study’s objective was todetermine retention in a specific age group with regard to adherenceto a number of visit types. This study was to determine how clinicalvisits could be achieved with consistency despite the limitationsprevalent in the specified age group (Stotmeyer et al. 2010). Thestudy concluded that other forms of visit other than conventionalclinic visits improved retention as well as diversifying the cohortsrelative to health status, age and physical functioning.
The study had several levels of evidence.First, the study used the power analysis in the form of p-value todefine whether the study had a goodlikelihood of generating a statistically noteworthy outcome if avariance actually exists in the population. Value for age stood at(p<0.001). On the other hand, the CHS for 1998-1999 had 79%, 4%,10%, and 2% for clinic, home, phone, and other visits respectivelywhile the CHS cohorts had 36.6%, 22.3%, and 41.1%.In line with the study’s literature review there was littleknowledge available with regard to retention rates relative to agegroup and visit type. Among older adults, consistent in-person visitsare critical due to physiological parameters, which had beenpreviously been lower due to aspects related to clinical depressionwith increasing age. The literature review accurately provided thatolder people present poor in-person visits more so in regard toclinic visits due to health, physical and cognitive functioning aswell as demographic attributes (Stotmeyer et al. 2010).
The findings from this study present valuableinformation, which can be used for further research and bepractically applied in clinical practice. Some of the threats tovalidity included older people’s difficulties in adhering tomedical advice. This may not be because of some personal accord butdue to limitations that come with old age. Health, geography, andlack of adjusted may have affected the reliability of the study, butthe study adjusted all the regressions used, utilized the chi square,split visits, and multiple comparisons. Cognitive, emotional,physical and social factors all play a part and the medicalprofession should accommodate these factors in presenting the bestcourse for health care provision for this particular age group.
Stotmeyer, E.S., Arnold, A. M., Boudreau, R. M., Ives, D.G., Cushman,M., Robbins, J. A., Harris, T. B., & Newmann, A. B. (2010).Long-term retention of older adults in the cardiovascular healthstudy: Implications for studies of the oldest old. The JournalAmerican Geriatrics Society, 58(4), 696-701.
Twisk, J. W. (2013). Applied longitudinal data analysis forepidemiology: a practical guide. Cambridge University Press.