SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The use of a historical control group is predicated on the assumption that survival and relapse-free survival in the historical control group closely approximate the survival and relapse-free survival in a randomized concurrent control group. This assumption has never been tested. This study compares survival and relapse-free survival in randomized control groups with historical control groups matched for disease, stage, and follow-up. Of the 43 matched control groups, 42% varied by more than 10 percentage points, 21% varied by more than 20 percentage points, and 5% varied by more than 30 percentage points. Of the 18 that varied by greater than 10 percentage points, 17 had superior survival or relapse-free survival in the randomized concurrent control group. This study indicates that the assumption that historical control groups may replace randomized concurrent control groups is not valid.
The literature reveals conflicting information regarding the extent to which psychogenic seizure patients have emotional disorders and neuropsychological deficits as compared with patients with epileptic seizures. Among groups matched for numbers of subjects, age, sex, and years of education, we observed that patients who had solely psychogenic seizures with either a major component of affectual expression or relatively minor motor activity were more disturbed emotionally than epileptic patients with partial seizures. In contrast, the personality characteristics of psychogenic seizure patients whose attacks had either little affectual display or prominent motor expression could not be distinguished from those of epileptic patients with convulsive generalized seizures. Closely matched groups of patients with solely psychogenic seizures, partial seizures, or generalized seizures did not differ in neuropsychological performance. However, psychogenic seizure patients performed much better on neuropsychological measures than a less-well-educated, but otherwise matched group of patients with generalized epileptic seizures.
OBJECTIVE: False pregnancy or delusional pregnancy, is the condition of believing one is pregnant despite factual evidence to the contrary. This is the first study to utilize a standardized mental disorder assessment tool, The Brief Psychiatric Rating Scale (BPRS) to evaluate a group of women with delusional pregnancy compared to a group of controls. METHOD: Eleven-women with delusional pregnancy (DP) were compared to a control group matched for age, race and DSM-IV psychiatric diagnosis. All patients were receiving care in a state psychiatric hospital setting. RESULTS: Compared to matched controls, women with DP had significantly higher levels of hostility (p < .05), higher rates of prescribed polypharmacy (p < .05) and a trend toward higher antipsychotic medication dosages (t = 1.48, df = 20, p = .08). These findings may be suggestive of greater resistance to treatment in women with DP. CONCLUSIONS: Biologic and psychotherapeutic treatment interventions for women with DP may need to address factors of hostility and treatment resistance. Preliminary treatment issues include selection of specific categories of psychotropic agents, as well as psychotherapies that are cognitive and lead to modification of belief paradigm.
STUDY DESIGN: This was a prospective study of patients (study group) with symptomatic disc herniations and asymptomatic volunteers (control group) matched for age, sex, and work-related risk factors. OBJECTIVE: To determine the prevalence of disc herniation in a matched group of asymptomatic volunteers and to access the diagnostic accuracy of magnetic resonance imaging, work perception, and psychosocial factors in identifying symptomatic disc herniations. SUMMARY OF BACKGROUND DATA: Disc herniations have been reported to occur in 20-36% of asymptomatic volunteers. A valid comparison of asymptomatic individuals and patients with disc herniations has not been performed. METHODS: Forty-six patients with low back pain and sciatica severe enough to require a discectomy were compared with 46 age-, sex-, and risk factor-matched (heavy lifting, twisting and bending, vibration, and sedentary activity) asymptomatic volunteers. Both groups had a complete clinical and magnetic resonance imaging examination and completed a questionnaire to assess differences in the psychosocial and work perception profiles. The prevalence and the severity of morphologic alterations (disc herniation, disc degeneration, and neural compromise) was analyzed by tow independent radiologists in a blinded fashion. Differences between both groups regarding MRI findings, work perception (occupational mental stress, intensity of concentration, job satisfaction, and job-related resignation) and psychosocial factors (anxiety, depression, self-control, social support, and marital status) were compared using multivariate techniques. Stepwise discriminating analysis was used to identify the best discriminating variables within the magnetic resonance image, work perception, and psychosocial categories in terms of the diagnostic accuracy to predict group membership (study [pain] or control [no pain] group). RESULTS: Matched controls had significantly more risk factors than a group of normal individuals. The present study has presented evidence that an age-, gender-, and occupational risk factors-matched group of asymptomatic patients shows a high incidence rate of disc herniations (76%). Although significantly less than the symptomatic group incidence of 96%, this represents a much higher prevalence rate than generally expected and reported in other studies of unmatched asymptomatic volunteers. Patients had more severe disc herniations (disc extrusions) than asymptomatic volunteers (35% vs. 13%). There was no significant differences regarding disc degeneration between both groups (96% vs. 85%). The only substantial morphologic difference between both groups was the presence of a neural compromise (83% vs. 22%), which was highly significant (P < 0.0001). There were significant differences between both groups regarding work perception (occupational mental stress, intensity of concentration, job satisfaction, and resignation; P < 0.027) and psychosocial factors (anxiety, depression, self-control, marital status; P < 0.0001). The best single predictor of a group membership was the extent of neural compromise. A combination of this factor with occupational mental stress, depression, and marital status was the best predictive model. With this model, the false-negative rate (potential overtreatment of disc morphology) was reduced by more than half compared with morphologic factors (nerve root compression) alone (22% vs. 11%). CONCLUSIONS: In an age-, sex-, and risk factor-matched group of asymptomatic individuals, disc herniation had a substantially higher prevalence (76%) than previously reported in an unmatched group. Individuals with minor disc herniations (i.e., protrusion, contained discs) are at a very high risk that their magnetic resonance images are not a causal explanation of pain because a high rate of asymptomatic subjects (63%) had comparable morphologic findings. The only highly significant difference between the study group and control group regarding morphologic fi
A two year follow-up of two matched groups of subjects with chronic severe mental illness was performed in order to evaluate a new psychiatric case management system. One group (n = 59) received care through psychiatric case management, using an assertive community treatment model that directly involved general practitioners. The other group, matched for age, sex, diagnostic group and number of hospital admissions, received standard outpatient care. Comparing the two years before and after case management, the experimental group showed a dramatic fall in inpatient admission days while the control group admission days remained the same (median difference in admission days across matched subject pairs = 64.5, 95% C.I. from 134.5 to 16). The experimental group remained out of hospital longer before first readmission (Kaplan-Meier survival analysis, P = 0.002). This type of case management programme can shorten or prevent admissions to psychiatric hospitals of patients with chronic mental illness, and increase their time before readmission.
Earlier identification of children with autism spectrum disorders (ASDs) is welcome, but presents a number of challenges to the clinical and the research enterprises (see Charman & Baird [2002] for a review). In the research enterprise, one critical methodological challenge is the use of appropriate measures on which to match groups of preschoolers with ASDs to comparison groups with other neurodevelopmental conditions. Language and communication impairments are central to the diagnosis of ASD and, therefore, critical variables to consider in group-matched research designs. In the domain of language function the challenges include the very poor language competence of many preschoolers with ASDs, the fact that some early language competencies form part of the formal diagnostic criteria of ASD and diagnostic algorithms on research diagnostic instruments, the uneven profile of language competency in children with ASDs, and the difference between performance on measures of formal language competency in the testing situation and everyday language use. The current paper will review these challenges and suggest some possible approaches to overcome them, including using more than one measure of language ability and adopting a pragmatic approach to group composition and statistical analysis.
Diabetic maculopathy (DMa) is a leading cause of visual loss in the western world. We examined whether plasma from type 2 diabetic patients with DMa contains factor(s) capable of inducing expression of the adhesion molecules E-selectin and VCAM-1 or cellular proliferation in cultured endothelial cells. Four gender-, age-, and duration (diabetes groups)-matched groups of 20 subjects each participated: 1) subjects with normal glucose tolerance (NGT), 2) subjects with impaired glucose tolerance (IGT), 3) type 2 diabetic patients without retinopathy, and 4) type 2 diabetic patients with DMa. Fasting plasma was added to in vitro-grown human umbilical vein endothelial cells for 6 h, after which E-selectin and VCAM-1 expression was measured. Proliferation was evaluated by thymidine incorporation. The individuals were characterized by measurement of 24-h ambulatory blood pressure, urinary albumin excretion rate, Hb A(1c), and blood lipids. Plasma from type 2 diabetic patients with DMa induced a significantly higher expression of E-selectin in endothelial cells than did plasma from subjects with NGT (259 +/- 23 x 10(3) vs. 198 +/- 19 x 10(3); arbitrary absorbance units; P < 0.05). There were no significant differences in plasma stimulatory effects on VCAM-1 expression or on thymidine incorporation between groups. These findings suggest that plasma from type 2 diabetic patients with DMa contains factor(s) capable of inducing the expression of E-selectin in endothelial cells. Enhanced expression of E-selectin may contribute to the development of DMa in type 2 diabetes.
Twenty-tree cases of pregnancy subsequent to mastectomy for carcinoma of the breast were observed. This association accounts for 8% of cases of breast carcinoma in potentially fertile women under 40. The overall prognosis is good, with a crude survival of 89% at 5 years and 70% at 10 and 15 years, superior to the figures observed in a control group matched for age, stage and date of treatment. Nevertheless, after elimination of the "selection effect" (pregnancy is more likely to occur in patients with a prolonged survival and no evidence of disease), no evidence of a biological effect of pregnancy was found: the prognosis in cases in which the delay from cancer to pregnancy is short is not different from the prognosis of the matched group. However, the disease free interval was longer in the pregnancy group.
The authors investigated whether the presence of a specific group goal would reduce social matching (i.e., matching one's own performance to the performance expected from others) by serving as an alternative standard. As predicted, when there was no specific goal, the participants matched their own performance to the performance expected from other group members. When there was a specific group goal, the women no longer engaged in social matching, although that effect did not emerge among the men. Instead, the women's mean personal performance was close to the performance level representing an equal share of the group goal. Moreover, the participants' perceptions of a fair contribution mediated the performance of the men and the women, both in the presence and in the absence of a goal.
OBJECTIVE: Uncross-matched blood either group specific or Group O is advocated in patients with exsanguinating haemorrhage when cross-matched blood cannot be made available rapidly. The risk of using uncross-matched blood is not known clearly. The purpose of this study is to attempt to quantify the risk of major transfusion reactions resulting from the use of uncross-matched group specific blood. METHOD: The cross-matching record of Patan hospital for the period of two years was analysed looking at the number of units that had major or minor incompatibility among all the cross-matching done during this period. RESULT: A total of 6027 units were cross-matched in two years. Only one unit of blood was found to have both major and minor incompatibility. All other units of blood taken out from the freeze for the purpose of cross-matching matched the patients blood. This puts the risk of having major transfusion reaction from incompatible blood when using uncross-matched group-specific blood at 1 in 6000. CONCLUSION: Using uncross-matched group specific blood in patients with severe haemorrhage, when delay in transfusion can put life at risk, is justifiable and needs to be encouraged.
OBJECTIVE: To determine whether the "goodness of fit" between infant cry characteristics and the mother's perception of the cry is related to developmental outcome at 18 months of age. DESIGN: This was a prospective, longitudinal study from birth to 18 months performed in a blinded manner. SETTING: The study was conducted in a maternity hospital, including normal and special care nurseries and a laboratory for developmental follow-up. PATIENTS: The 121 term and preterm infants and their mothers were selected to meet medical criteria. MEASUREMENT: Acoustic analysis of 1-month infant cry and the mother's perception of the same cry was used to divide subjects into four groups representing matches and mismatches between infant cry characteristics and maternal cry perception. Primary outcome measures of cognitive, language, motor, and neurologic outcome were administered at 18 months. Caretaking environment measures were also recorded. RESULTS: Statistically significant (P < .05) findings showed that matched groups scored higher on measures of language and cognitive performance than infants in the mismatch groups, with a particular advantage for infants in the matched group in which mothers accurately perceived the higher-pitched cries of their infants. There were no differences between the groups in biologic or sociodemographic factors. Group differences were observed in social support and maternal self-esteem. CONCLUSIONS: Matches and mismatches between infant cry characteristics at 1 month and the mother's perception of the cry are related to cognitive and language outcome at 18 months in term and preterm infants. This relation is probably due to transactional processes in which developmental outcome is affected by the clarity of the infants' signals and by the ability of the mother to accurately perceive her infant's signals. The mother's ability to read her infant's cues may be affected by factors such as social support and self-esteem.
OBJECTIVE: To determine the effect of spinal cord stimulation (SCS) on limb survival in patients with non-reconstructable critical leg ischaemia, and the value of patient selection on the basis of transcutaneous oxygen pressure (TcpO2) measurements and trial screening. DESIGN: A prospective, controlled, European multicentre study. METHODS: Non-reconstructable patients with stable critical leg ischaemia were divided into three groups. The SCS-Match group comprised patients with a baseline forefoot TcpO2 of < 30 mmHg and both sufficient pain relief and sufficient paraesthesia coverage (> 75%) after a test stimulation period of at least 72 h. If baseline TcpO2 was < 10 mmHg, the TcpO2 should have exceeded 20 mmHg after test stimulation. The SCS-Match group was compared with patients not meeting these criteria, who were treated either with SCS (SCS-No-Match) or without SCS (No-SCS). RESULTS: At baseline, the mean (+/- SD) supine TcpO2 was 14.9 +/- 8.3 mmHg in the SCS-Match group (n = 41), 11.3 +/- 13.3 mmHg in the SCS-No-Match group (n = 32) and 15.3 +/- 17.1 mmHg in the No-SCS group (n = 39). In the SCS-Match group a significant improvement in pain relief (p < 0.005) and TcpO2 (p < 0.001) was seen. After 12 months, cumulative limb survival of patients treated with SCS was significantly better than that of patients not treated with SCS (p < 0.03), and limb survival in the SCS-Match group was significantly higher (p < 0.03) than that in the SCS-No-Match and No-SCS groups (78, 55 and 45%, respectively). CONCLUSION: SCS treatment of non-reconstructable critical leg ischaemia provides a significantly better limb survival rate compared with conservative treatment. Patient selection based on TcpO2 and the results of trial screening further increase the probability of limb survival after SCS therapy.
Serum albumin (sALB) is routinely determined in blood tests and is an excellent predictor of risk for many medical illnesses. Hypoalbuminemia has been sporadically reported in patients with psychiatric disorders, such as major depressive disorder and schizophrenia. We compared sALB levels between 19 drug-free patients of major depressive disorder with a control group of matching diets. We conducted this study by controlling the nutrition factor by assessing patient's diets, as well as other possible confounding factors such as sex, age, body mass index (BMI), liver function, and exercise, while focusing on hypoalbuminemia in patients with major depressive disorder. There is no difference in age, gender distribution, and dietary frequency on protein and albumin intake between the patient and control group. The sALB levels of the group with major depressive disorder were significantly reduced (p=0.049). The severity of depression is negatively correlated to the sALB level (r=-0.46, p=0.04). Hypoalbuminemia has clinical meanings on severity of depression and is independent of malnutrition. However, our results can only be seen as very preliminary and should be confirmed by larger studies.
To determine the relative risk of complications in treating ankle fractures in patients with diabetes, we compared the results of the management of displaced malleolar fractures in 26 patients with those of a matched group of non-diabetic patients, using a case-controlled study. The groups were matched for patient age, fracture type and treating surgeon. The incidence of significant complications in diabetic patients was 42.3%. By contrast, there were no complications in the matched group of non-diabetic patients. Of 19 diabetic patients treated surgically, six developed major complications including one case of malunion, one of necrosis of the wound edge requiring a flap, and two of deep sepsis. Two patients required amputation and both died. Diabetic patients with displaced ankle fractures treated non-operatively had a high incidence of loss of reduction and malunion but these caused few symptoms. In these patients, non-operative management may be preferable in view of the high risks of major complications after surgery and the acceptance of malunion by the older patient with lower demands.
An achromatic phase-matching scheme is reported for an optical parametric oscillator in tilted quasi-phase-matched gratings. The spectral angular dispersion is introduced in interaction waves such that each wave component satisfies the two-dimensional (noncollinear) quasi-phase matching. This is equivalent to simultaneous quasi-phase matching and group-velocity matching for ultrashort pulses. The phase-matching bandwidth for 10 mm periodically poled KTP increases by a factor of 12 at lambdas = 1.7 microm compared with one-dimensional quasi-phase matching. The effective interaction length will increase as a result of the matching.
Large nonlinear phase shifts were generated with femtosecond pulses at 1560 nm through cascaded quadratic interactions in periodically poled MgO-doped LiNbO3. The off-diagonal component of the nonlinear coefficient was utilized for simultaneous quasi phase matching and group-velocity matching. The effective nonlinear refractive index was varied from -2.9 x 10(-14) to +3.3 x 10(-14) cm2/W by tuning the phase-mismatch conditions.