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PubMed1992

Impact of a matched term control group on interpretation of developmental performance in preterm infants.

One hundred twenty-four children who were born at 24 to 31 weeks' gestation and 124 term children matched in social background underwent serial developmental evaluations. The Bayley Mental Developmental Index at 6, 15, and 24 months and the McCarthy General Cognitive Index at 4 years were used to classify cognitive outcome for preterm children as normal (indices higher than 1 SD below the mean), mild-moderately delayed (indices between 1 and 2 SD below the mean), or severely delayed (indices > or = 2 SD below the mean). Classifications based on norms derived from the performance of the term control group were compared with those based on published standardized test scores. The control group had substantially higher mean (+/- SD) Bayley Mental Developmental Indices at 6 (111 +/- 11), 15 (114 +/- 13), and 24 months (115 +/- 21) than the published test mean (100 +/- 16). Consequently, significantly more preterm children were classified as normal when the Bayley test mean was used than when the performance of the control group was used to define the normal range (84% vs 52% at 6 months, 82% vs 49% at 15 months, and 70% vs 47% at 24 months). Severe cognitive delays were infrequent when defined by test mean (6% to 11%) but two to three times greater when the control group scores were used. In contrast, the control group had a mean McCarthy General Cognitive Index at 4 years (102 +/- 14) that was similar to the published test mean (100 +/- 16).(ABSTRACT TRUNCATED AT 250 WORDS)

Child Development↗
PubMed2002

A randomized clinical trial comparing general exercise, McKenzie treatment and a control group in patients with neck pain.

Seventy-seven patients with neck pain in the primary health care were included in a prospective, randomized clinical trial and randomly assigned to general exercise, McKenzie treatment, or a control group. Seventy patients completed the treatment; response rate 93% at 12-month follow-up. All three groups showed significant improvement regarding the main outcomes, pain intensity and Neck Disability Index, even at 12-month follow-up, but there was no significant difference between the groups. In all, 79% reported that they were better or completely restored after treatment, although 51% reported constant/daily pain. In the McKenzie group compared with the control group, a tendency toward greater improvement was noted for pain intensity at 3 weeks and at 6-month follow-up, and for post-treatment Neck Disability Index. Significant improvement in Distress and Risk Assessment Method scores was shown in the McKenzie group only. The three groups had similar recurrence rates, although after 12 months the McKenzie group showed a tendency toward fewer visits for additional health care. The study did not provide a definite evidence of treatment efficacy in patients with neck pain, however, there was a tendency toward a better outcome with the two active alternatives compared with the control group.

Adult↗
PubMed1983

The prevalence of coffee drinking among hospitalized and population-based control groups.

Data on coffee-drinking habits obtained from a case-control study conducted in Detroit were used to compare the proportions of coffee drinkers in a hospital and a population control series. The comparison was based on interviews with 262 hospitalized controls and 427 population controls. The overall proportion of coffee drinkers in the total hospital control group was similar to that in the population control group. However, the proportion of moderate-to-heavy coffee drinkers among controls hospitalized for conditions that may have caused them to alter their diet (eg, gastrointestinal disorders and cardiovascular disease) was lower than that among population controls. In contrast, the proportion of moderate-to-heavy coffee drinkers among controls hospitalized for conditions that probably did not cause a change in diet (eg, fractures) was almost identical to that among population controls. These results suggest that, in hospital-based case-control studies of the effects of coffee consumption, it would be prudent to restrict the referent group to those patients hospitalized for conditions that probably did not cause a change in diet. The magnitude of bias resulting from failure to exclude controls hospitalized for diet-altering conditions will depend on two factors that may vary between studies: (1) the distribution of diet-altering conditions among the hospital controls, and (2) the relationship of these diseases to coffee consumption.

Adult↗
PubMed2003

Cost savings for a preferred provider organization population with multi-condition disease management: evaluating program impact using predictive modeling with a control group.

Disease management programs have historically had difficulty demonstrating the financial value of their programs using statistically rigorous methods. This preliminary study utilized a predictive model built from a control group that consisted of individual employer groups whose benefits managers did not purchase disease management. The purpose of this evaluation was to examine the cost savings associated with Health Management Corporation's disease management program for asthma, diabetes, and coronary artery disease. Study and control group members were identified with exactly the same selection criteria as self-insured employer groups (n = 76,194) with preferred provider organization health plans that offered the disease management program. The study group consisted of members (n = 1,009) who were identified as having any of the three conditions and were eligible for the disease management program, regardless of the extent of their participation. The control group included members (n = 2,491) who were identified as having any of the same three conditions. The control group data were used to develop a predictive model designed to calculate expected medical claims costs for the study group. The gross savings of the disease management program was measured by calculating the difference between the expected medical claims costs predicted by the model and the actual medical claims costs for the study group. Preliminary analyses indicate that Health Management Corporation's disease management program produced a return on investment of $2.84: $1.00 and $1.45 gross savings per member per month.

Adolescent↗
PubMed1994

Neurocognitive abilities for a clinically depressed sample versus a matched control group of normal individuals.

Depressed patients have been reported to show deficits in tasks that demand memory, planning/sequencing, speeded responding, and effortful responding. Many studies of depressed patients have used inadequate instrumentation or poor control groups. In this investigation, the cognitive performance of 44 patients diagnosed as clinically depressed was compared with the performance of a control group of normal individuals that closely matched the clinical group on the variables of age, gender, race or ethnic group, and educational attainment. The groups were compared on the tasks that compose the Kaufman Adolescent and Adult Intelligence Test (KAIT), which includes reliable and valid measures of most pertinent areas of purported deficit in depressed patients. Multivariate analyses of variance indicated that the depressed and control groups did not differ significantly on KAIT variables, but the depressed patients did differ significantly from the control group on the delayed versus immediate recall of verbal information.

Adolescent↗
PubMed2026

Does Inquiry-Based Learning Improve Students' Critical Thinking? A Meta-Analysis Accounting for Control Group Variations.

BACKGROUND: Inquiry learning is widely recognized, through empirical studies, as an appropriate instruction in enhancing students' critical thinking, yet the results were varied across context. The previous meta-analysis did not include the control group variations as a potential moderator and the studies subject domain was limited only to science subjects. Consequently, it is difficult to generalize the effectiveness of IBL in enhancing critical thinking. This meta-analysis aims to investigate whether inquiry learning is effective in improving the students' critical thinking skills and examine the moderating roles of each study characteristic. Methods The literature search applying the PRISMA protocol 2020 was conducted by utilizing SCOPUS, ERIC, and DOAJ databases. A total of 57 studies from 51 articles, published from 2015 to 2025, were synthesized using a random-effects model with standardized mean difference (SMD). RESULTS: The analysis revealed that IBL has a large and significant effect on enhancing students' critical thinking (g = 1.336; 95% CI [1.061, 1.611]). However, substantial heterogeneity was observed (I 2 = 92.09%), suggesting variability across contexts. Moderator analyses revealed that the main moderator, control group variations, was statistically significant in moderating the effectiveness of IBL (Qm = 5.21; p = .022). in contrast, subject domain (Qm = 1.43; p = .698), education level (Qm = 1.11; p = .774), and country ( Q m  = 3.33; p = .650), were insignificantly moderating the effectiveness of inquiry learning. CONCLUSIONS: The present meta-analysis highlighted that IBL is effective in improving students' critical thinking. However, the effectiveness of IBL was relative to the type of control group variations. Its effect on critical thinking was greater when compared with teacher-centered learning but smaller when compared with other student-centered learning.

Thinking↗
PubMed2003

Repeatability over time of posture, radiograph positioning, and radiograph line drawing: an analysis of six control groups.

BACKGROUND: There is debate concerning the repeatability of posture over time, radiograph positioning repeatability, and radiograph line drawing reliability. These ideas seem to negate the use of before-and-after spinal radiographic imaging to detect and correct vertebral subluxations. OBJECTIVE: To review the results of control groups in 6 clinical control trials with before-and-after radiographic measurements taken days, weeks, months, or years apart to accept or reject the hypothesis that radiographic analysis procedures are not repeatable, reliable, or reproducible. DATA SOURCES: Six published control groups from original data. Other data were obtained from searches on MEDLINE, CHIROLARS, MANTIS, and CINAHL on radiographic reliability, posture, and positioning. RESULTS: Comparison of initial and follow-up radiographic data for 6 control groups indicate that measured angles and distances between initial and follow-up radiograph measurements on lateral and anterior to posterior radiographs are not significantly different when utilizing Chiropractic Biophysics radiographic procedures. In 48 out of 50 measurements, the differences between initial and follow-up radiographs are less than 1.5 degrees and 2 mm. These measurements indicate that posture is repeatable, radiographic positioning is repeatable, and radiographic line drawing analysis for spinal displacement is highly reliable. The scientific literature on these topics also indicates the repeatability of posture, radiographic positioning, and radiographic line drawing. CONCLUSIONS: Posture, radiographic positioning, and radiographic line drawing are all very reliable/repeatable. When Chiropractic Biophysics standardized procedures are used, any pre-to-post alignment changes in treatment groups are a result of the treatment procedures applied. These results contradict common claims made by several researchers and clinicians in the indexed literature. Chiropractic radiologic education and publications should reflect the recent literature, provide more support for posture analysis, radiographic positioning, radiographic line drawing analyses, and applications of posture and radiographic procedures for measuring spinal displacement on plain radiographs.

Biomechanical Phenomena↗
PubMed1996

Cementless total knee arthroplasty in obese patients. A comparison with a matched control group.

The heaviest 45 patients (50 knees) who underwent cementless total knee arthroplasty were compared with a matched control group of 45 total knee arthroplasty patients (50 knees) with respect to clinical and radiographic data. Surgery was performed over a 10-year period (1980-1989) and follow-up evaluation averaged 7 years (range, 2-11 years). The control group consisted of nonobese patients matched to the obese group with respect to age, sex, diagnosis, preoperative deformity, and length of follow-up evaluation. Clinical evaluation was made using the Knee Society rating scale as well as an analysis of multiple other clinical parameters. Radiographically, each patient was evaluated with long-standing anteroposterior views, lateral and patellar views, and spot fluoroscopic views of the involved knee. This evaluation included an analysis of lucencies, bead shedding, and prosthetic alignment. The final average clinical score in the obese group was 88 points with four revisions, and that for the control group was 91 points with two revisions. There were no significant differences in the combined percentage of good and excellent results between the two groups. On the basis of the results of this study, it is believed that weight as a factor by itself should not compromise the early (7-year average follow-up period) results of total knee arthroplasty.

Adult↗
PubMed2005

Placebo control groups in trials of major depressive disorder among older patients.

BACKGROUND: Ethical concerns have been raised regarding the continued use of placebo control groups in randomized controlled trials of antidepressant medications for major depressive disorder. These concerns may be especially relevant for geriatric patients who may experience significant morbidity related to major depressive disorder. METHODS: Sixty-eight randomized placebo-controlled trials of antidepressant medication for major depressive disorder were examined, 6 of which measured response to medication and placebo in elderly patients. RESULTS: Although this review is limited by the small number of studies focusing on older individuals, there are a number of similarities and some differences in geriatric studies in comparison to other studies of adults with major depressive disorder. In comparison to studies of younger adults, the proportion of patients responding to placebo in studies of older individuals was slightly higher, and the proportion of patients responding to active medication was lower, leading to a significantly reduced effect size. CONCLUSIONS: The scientific importance of using control groups in studies of major depression poses ethical challenges. However, the substantial and variable response to placebo and the inability to predict accurately the response to placebo or medication raise serious doubts about the scientific value of trials of new medications in which there is no placebo group.

Adult↗
PubMed1990

[Minimal lipid anomalies in a group of men with early coronary disease compared to a control group].

A group of 27 men with early coronary disease (mean age: 52 years) with cholesterol levels below 6.45 mmol/l and triglycerides levels below 2.3 mmol/l, who underwent a coronary angiography, is compared with a control group of 18 men (CG) with normal angiography. The only significant differences between the two groups are: a triglycerides levels slightly higher in the CM group (1.55 + 0.4 mmol/l) vs 1.18 +/- 0.37 mmol/l, p 0.001), a HDL-cholesterol level slightly lower in the CM group (1.08 +/- 0.19 mmol/l vs 1.26 +/- 0.21 mmol/l, p 0.01) and an Apo AI/Apo B ratio slightly lower in the CM group (1.02 +/- 0.24 vs 1.18 +/- 0.17, p 0.005). In the CM group, 21 patients in 27 present a lipid abnormality requiring, according to the European consensus recommendations, the prescription of hygieno-dietetic measures. In the CM group, 10 patients in 18 present a minimal lipid abnormality, also requiring hygieno-dietetic measures. These results are compared with the recommendations of the European consensus.

Coronary Disease↗
PubMed2001

[Assessment of nociceptive suppression in laparoscopic postoperative status: prospective, randomized and comparative study with a control group].

In recent years endoscopic surgery has became a highly demanded procedure because it is an easy method for diagnosis and treatment in gynecological field. Post-operative pain is considered as a condition in the morbidity status. The objective of this study was to evaluate the nociceptive suppression in laparoscopic surgery. A prospective randomized trial was performed in order to evaluate this condition. A total of 45 patients were included. Three groups were randomized using two different anesthetics applied in the cult-de-sac and uterine-bladder union. Group A (n-15) received bupivacaine, group B (n = 15) ropivacaine and group C (control) saline solution was instilled. The pain was scored using the visual analog scale as same as blood pressure and heart rate in a 15 minute intervals in the recovery room. For study design there were no differences in age, weight, height and body mass index (EMI). The surgical and anesthetic times were similar among groups. However there were significant differences when pain was evaluated. For a less toxic effects and good preventive analgesia we recommend to use ropivacaine in the postoperative status.

Adolescent↗
PubMedDate not supplied

[Acute diarrhea in children less than 3 years of age: Enteropathogens isolated in patient's stools, compared with a control group]

OBJECTIVES: To observe the occurrence of different etiological agents of acute diarrhea (AD) in stool specimens of patients and children in a control group. MATERIAL AND METHODS: 100 children less than three years of age with AD were studied as well as 100 controls, between November 1993 and May 1994. Stool specimens were collected in both groups and the following enteropathogens were searched for: Rotavirus, Escherichia coli (EPEC, ETEC, EIEC, EHEC), Salmonella sp, Shigella sp, Campylobacter jejuni, Campylobacter coli, Yersinia enterocolitica, Cryptosporidium sp, Giardia lamblia, Entamoeba histolytica. Statistical analysis using the exact Fisher test (at significance level p<0,05) was done. The mean age was 12,5 months, with more cases in patients less than 6 months (35%). Children were seen at the emergency section on an average fifth day after the start of the diarrhea. Most came from homes with basical sanitary conditions. Watery diarrhea was more frequent than bloody diarrhea with mucus, at a proportion of 4:1. RESULTS: Rotavirus was the most frequent agent: 21% in the AD group and 3% in the control group (p= 0,0001). Shigella sp was isolated in 7% of the AD group and none of the control group (p= 0,0140). EPEC was detected in 13% of AD cases and 7% in the control group (p= 0,2381) but the classical subgroups O55, O111, O119 were only isolated from the patients with AD. The other enteropathogens were infrequently detected or in equal proportion in both groups. Rotavirus and EPEC were the more frequently isolated agents in watery diarrhea, while Shigella sp was the predominant agent found in bloody stools with mucus. CONCLUSIONS: Rotavirus was the most common causative agent in AD. The detection of Rotavirus and Shigella sp nearly exclusively in patients with AD confirms the high patogenicity of these etiological agents when compared to the others. Escherichia coli (EPEC) diagnosed by polyvalent sera does not confirm its respective diarrheogenic property due to isolation in the same proportion among patients with AD and controls. Monovalent antisera made possible the detection of classical subgroups of EPEC O111, O119, O55 isolated only from AD patients, confirming the already known high patogenicity of these strains.

Journal Article↗
PubMed2003

Corneal autofluorescence in relation to permeability of the blood-aqueous barrier in diabetic patients with clinically significant macular edema and in an age-matched control group.

PURPOSE: Corneal autofluorescence is related to advanced glycation end products formed by glucose that reaches the cornea via the aqueous humour. The aim of the study was to examine the influence on autofluorescence of changes in permeability of the blood aqueous barrier. METHODS: Corneal autofluorescence was measured in 50 diabetic patients with clinically significant macular edema and in 28 age-matched control subjects. Permeability of the blood aqueous barrier was assessed using the diffusion coefficient of fluorescein. RESULTS: Corneal autofluorescence was higher in diabetic subjects than in the control group, mean (SD) at an excitation wavelength of 458 nm was 41.2 ng f-eq/ml (11.7) in diabetic patients and 26.5 ng f-eq/ml (7.3) in the control group, p < 0.001. The mean permeability of the blood aqueous barrier, Kd(F), was 492.0.10(-6) min(-1 )in the diabetic patients and 484.2. 10(-6) min(-1)in the control group. There was no association between permeability of the blood aqueous barrier and corneal autofluorescence, p = 0.99 for the diabetic patients and p = 0.15 for the control group (458 nm). CONCLUSIONS: Corneal autofluorescence was unaffected by permeability of the blood aqueous barrier suggesting that formation of advanced glycation products is limited by other factors than the concentration of glucose in the aqueous humour, or that other factors unrelated to nonenzymatic glycation of stromal proteins are involved.

Adult↗
PubMedDate not supplied

Reducing sample sizes when comparing experimental and control groups.

In comparing rates for two groups (one control and the other experimental), one may use an historical control to reduce the sample size needed for a test of significance to one-fourth that required if the control is not historical. If there is some doubt as to whether one's control is comparable to the historical control, a test showing the equality of the historical and experimental controls can lead to a halving of the sample required for significance testing. This same argument also applies to the comparison of two means.

Research Design↗
PubMed1987

Control group selection in studies involving compensation for occupational diseases.

Many occupational diseases which are compensable are of interest in epidemiological studies. In addition, diseases of interest which are not compensable may be discovered during the evaluation of eligibility for compensation. Certain peculiarities of the group of workers who seek compensation (those who receive compensation and those who do not) may make the selection of an appropriate control group difficult. In two recent studies, problems associated with finding controls for cases with a compensable disease and a disease discovered during the evaluation of eligibility for compensation pointed out some of these potential biases. This paper describes the results obtained using different control groups for these studies, proposes reasons for differences in the results and suggests steps which can be taken to ensure the validity of a control group in such studies.

Arthritis, Rheumatoid↗
PubMed2000

Selection of control groups by using a commercial database and random digit dialing.

Identifying a control group when cases come from a specialized hospital is a challenge for epidemiologists. The authors compared controls recruited by using a commercial database with those recruited by random digit dialing in the context of a hospital-based case-control study of ovarian cancer. This part of the study was conducted in 1997-1998 among women aged 18 years or older who resided in the New York metropolitan area. A mailing list owner grouped cases into "lifestyle" clusters based on US zip+4 postal code microneighborhoods and generated a random sample of potential controls with the same distribution across the clusters. Controls recruited from the commercial database (n = 82) and from random digit dialing (n = 90) were similar in age and race. Women from the commercial database had somewhat more education and higher incomes and were more similar to the cases on these measures. The control groups resembled each other closely in terms of oral contraceptive use, nulliparity, and religion and differed from the cases on these measures. Response rates were similar for the two groups. Only 28% of the cases were included on the mailing list, indicating that it did not reflect the source population of the cases. Use of a commercial database provided a control group whose socioeconomic factors were similar to those of cases at a lower cost than when random digit dialing was used but did not result in a higher response rate.

Adult↗
PubMed2000

The temporomandibular opening index (TOI) in patients with closed lock and a control group with no temporomandibular disorders (TMD): an initial study.

Mandibular movement may be assessed by measuring maximum mouth opening. This is a linear measurement from the maxillary to the mandibular incisal edge and is affected by gender, age and ramus length. It cannot be used to classify patients. The temporomandibular opening index (TOI) appears to be independent of these variables and has been shown to differ for different categories of patients with temporomandibular disorders (TMD). This study examined the TOI in a group of 11 patients with closed lock and a control group of 11 individuals with no signs or symptoms of TMD. The group with closed lock had a significantly different TOI from that of the control group (P < 0.001) according to the Mann-Whitney U-test. This suggests that the TOI may have greater diagnostic value than linear mouth opening.

Adult↗