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C K Kwoh

Publications and source records attributed to C K Kwoh.

36 records · Page 2Linked to original sources
PubMed1995

Incidence of systemic lupus erythematosus. Race and gender differences.

OBJECTIVE: To examine racial differences in the incidence of systemic lupus erythematosus (SLE). METHODS: A population-based registry of SLE patients in Allegheny County, Pennsylvania, was used to identify incident cases of SLE diagnosed between January 1, 1985 and December 31, 1990, from 3 sources, by medical record review (University of Pittsburgh Lupus Databank, rheumatologists, and hospitals). Capture-recapture methods using log-linear models were used to estimate the level of case-finding and to calculate 95% confidence intervals (CI). Incidence rates were calculated per 100,000 population. RESULTS: A total of 191 definite and 78 probable incident cases of SLE were identified, and the overall annual incidence rates were 2.4 (95% CI 2.1-2.8) and 1.0 (95% CI 0.8-1.3), respectively. The crude incidence rates of definite SLE were 0.4 for white males, 3.5 for white females, 0.7 for African-American males, and 9.2 for African-American females. The annual incidence rates of definite SLE remained fairly constant over the study interval. African-American females with definite SLE had a younger mean age at diagnosis compared with white females (P < 0.05). Since the overall ascertainment rate was high (85%; 95% CI 78-92%), the ascertainment-corrected incidence rate for definite SLE, 2.8 (95% CI 2.6-3.2), was similar to the crude rate. CONCLUSION: Our rates clearly confirm previous reports of an excess incidence of SLE among females compared with males and among African-Americans compared with whites. We have used capture-recapture methods to improve the accuracy of SLE incidence rates, and we advocate their use to facilitate comparisons across studies.

Adolescent↗
PubMed1995

Effect of growth factors on the proliferation of fibroblasts from the medial collateral and anterior cruciate ligaments.

Growth factors have been shown to stimulate fibroblast division and thus may influence ligament healing. We analyzed the effects of individual growth factors on the proliferation of fibroblasts from the medial collateral and anterior cruciate ligaments of the rabbit in vitro in order to identify growth factors that might enhance proliferation of fibroblasts and to compare the responses of the fibroblasts from the two ligaments to these growth factors. Through measurement of the uptake of [3H]-thymidine into DNA, fibroblasts from these ligaments that had been treated with epidermal growth factor and basic fibroblast growth factor were found to proliferate nearly eight times more than control fibroblasts. Additionally, the fibroblasts of both ligaments proliferated at similar rates when exposed to platelet-derived growth factor-AA, platelet-derived growth factor-BB, basic fibroblast growth factor, insulin-like growth factor-1, and interleukin-1-alpha. However, epidermal growth factor and transforming growth factor-beta caused the fibroblasts from the medial collateral ligament to proliferate at a rate 1.3-1.4 times greater than that of fibroblasts from the anterior cruciate ligament. The reverse was true with acidic fibroblast growth factor, which stimulated the fibroblasts from the anterior cruciate ligament to proliferate at a rate 1.3-1.6 times greater than that of fibroblasts from the medial collateral ligament. This study demonstrated that growth factors can stimulate cell division in ligaments and may be effective in enhancing ligament healing but that these differences were not great enough to explain fully the clinical differences observed between healing of the medial collateral and anterior cruciate ligaments.

Animals↗
PubMed1995

Antiphospholipid antibodies in pediatric systemic lupus erythematosus.

OBJECTIVE: Antiphospholipid antibodies (aPLs) have been extensively studied in adults with systemic lupus erythematosus (SLE) and have been associated with arterial and venous thrombosis, thrombocytopenia, neurologic disorders, and recurrent fetal loss. In contrast, very little is known about the frequency and clinical significance of aPLs in pediatric SLE. This study was designed to determine the frequency of aPLs in pediatric SLE and the temporally associated clinical manifestations. DESIGN: We studied 29 consecutive patients with onset of SLE in childhood seen in the Pediatric Rheumatology Clinic at the University of Pittsburgh, Children's Hospital, between 1985 and 1992. We defined aPL as the presence of a lupus anticoagulant (LAC), immunoglobulin G or immunoglobulin M anticardiolipin antibodies (aCLs), or a biologic false-positive serologic test for syphilis determined by a VDRL test. Clinical manifestations were temporally correlated to the presence of aPLs if they occurred within 6 months. RESULTS: Overall, 19 (65%) of 29 children with SLE had one of the three laboratory abnormalities defining aPL. LAC was detected in 16 (62%) of 26, aCL in 18 (66%) of 27, and false-positive VDRL test results in 11 (39%) of 28. Twenty-five of the 29 patients had all three tests performed. In 10 patients, all three tests were abnormal. The presence of thrombosis in 7 patients (4 venous, 2 arterial, and 1 both) was associated with a positive aPL, specifically aCL. The presence of an aPL was significantly associated with anti-double-stranded DNA antibodies, but not with neuropsychiatric manifestations or with thrombocytopenia. The presence of an aCL was significantly associated with hemolytic anemia. A prolonged prothrombin time, in the setting of an LAC (all with a prolonged activated partial thromboplastin time), was associated with life-threatening disease in 6 of 15 patients. CONCLUSION: Sixty-five percent of 29 consecutive pediatric patients with SLE had evidence of aPL. The presence of aPL, specifically aCL, was significantly associated with thrombotic events. The presence of a prolonged prothrombin time in the setting of an LAC may be a marker of more serious disease in pediatric SLE.

Adolescent↗
PubMed1995

Genetic epidemiology of rheumatoid arthritis.

We conducted family studies and segregation analyses of rheumatoid arthritis (RA) that were based on consecutive patients with RA ascertained without regard to family history or known risk factors. First-degree relatives from 135 simplex and 30 multiplex families were included in the analyses. A highly penetrant recessive major gene, with a mutant allele frequency of .005, was identified as the most parsimonious genetic risk factor. Significant evidence for heterogeneity in risk for RA was observed for proband gender but not for proband age at onset. Kaplan-Meier risk analysis demonstrated significant evidence for differences in the distribution of risk among first-degree relatives. These analyses demonstrated that both proband gender and age at onset are important risk factors but that proband gender appears to be the more important determinant of risk, with relatives of male probands having the greatest cumulative risk for RA. In addition, log-linear modeling identified proband gender, familiality (multiplex or simplex), and an interaction term between these two variables as being adequate to define the distribution of risk in families. The pattern of risk for RA among susceptible individuals and its inheritance is thus heterogeneous. For future genetic analyses, families with an excess of affected males having a young age at onset may be the most informative in identifying the putative recessive gene and its modifiers.

Adult↗
PubMed1995

Variability in the attainment of functional milestones during the acute care admission after total joint replacement.

OBJECTIVE: To quantify patients' functional improvement in the immediate postoperative period after total hip arthroplasty (THA) or total knee arthroplasty (TKA). METHODS: A prospective observational study design was used to examine the number of physical therapy treatment sessions and postoperative days required to attain independence in 4 critical functional milestones, with independence defined as the ability to perform the activity without the assistance of another person. The 4 functional milestones selected were the ability to perform supine to sit transfers; sit to stand transfers; ambulation to 100'; and the ability to climb stairs. Consecutive patients undergoing elective THA or TKA for the first time at a community teaching hospital were entered into the study. RESULTS: The study group consisted of 81 patients undergoing elective THA or TKA (33 THA and 48 TKA). There was wide variability in the number of physical therapy sessions and postoperative days required to attain each of the 4 milestones and all 4 milestones. Climbing stairs was the most difficult task, followed by walking 100', performing sit to stand transfers, and performing supine to sit transfers. The achievement of the latter 2 milestones was similar. CONCLUSION: Our examination of patients' progress in attaining specific functional milestones is a unique approach to outcome assessment that emphasizes the physical therapy aspect of postsurgical rehabilitation. A wide variability in patients' functional progress during the acute care admission after elective THA or TKA was demonstrated. The reasons for this variability need to be explored since they may have important implications for planning rehabilitation related to THA, TKA or other orthopedic reconstructive procedures.

Adult↗
PubMed1993

Ascertainment corrected rates: applications of capture-recapture methods.

Accurate rates, though fundamental to epidemiology, are often very difficult to obtain. Incidence, prevalence, and mortality rates have traditionally been established through either passive reporting surveillance systems, through active surveillance systems, or by a combination of the two methods. Typically, when researchers employ these approaches they do not formally evaluate or correct for the degree of underascertainment. Undercount of cases is a potent determinant of rates which we cannot continue to ignore. We believe all rates should be adjusted for underascertainment in order to achieve a truer picture of the risk and risk factors of disease. Here, we present a procedure to ascertainment correct rates based upon well established capture-recapture methods.

Epidemiologic Methods↗
PubMed1993

Serum sex hormones and severity of osteoarthritis of the hand.

OBJECTIVE: To examine the relationship of endogenous sex hormones to the severity of radiographic hand osteoarthritis (ROA) in 229 white women, mean age 74 years. METHODS: Hand ROA was graded according to the Kellgren-Lawrence scale and according to individual features of OA: osteophytes, joint space narrowing, subchondral sclerosis, lateral deformity and joint collapse. Two measures of hand ROA were considered: the worst joint score assigned to any one of 10 hand joints and the sum of the scores for the 10 joints. RESULTS: Comparison of the age and obesity adjusted sex hormone concentrations by the worst Kellgren-Lawrence score or the worst score of the individual features of OA revealed little difference. There were no trends in the sex hormone concentrations with increasing severity of hand ROA. CONCLUSIONS: Our results do not support an association between endogenous hormone levels and severity of hand ROA.

Aged↗
PubMed1992

Randomized, controlled trial of compression gloves in rheumatoid arthritis.

A randomized, controlled trial was conducted to determine efficacy of the Isotoner and the Futuro compression gloves in 39 patients with hand synovitis secondary to rheumatoid arthritis. After 7 days of nighttime treatment, both brands of gloves were found to decrease subjective symptoms of pain and stiffness (p < 0.05). In addition, swelling of the proximal interphalangeal joints decreased, while range of motion, rate of finger motion, and grip strength all increased (p < 0.05). Compression gloves should be used with caution in patients with bilateral carpal tunnel syndrome, because 12 of 13 such patients experienced worsening of their symptoms following one nighttime wearing of compression gloves. While both gloves were found to be efficacious in improving the signs and symptoms of hand synovitis, neither glove was found to be superior to the other. Patient preferences related to glove composition and fit may ultimately determine which glove to prescribe.

Adult↗
PubMed1992

Epidemiology of the rheumatic diseases.

Replication of similar findings in diverse study populations using different study designs provides important evidence for causal inferences regarding risk factors reported in epidemiologic studies. Risk factors for knee osteoarthritis have been substantiated in a number of cross-sectional and longitudinal cohort studies. Longitudinal cohort studies have also added to our understanding of risk factors associated with hip osteoarthritis and hand osteoarthritis. In contrast, studies of hormonal and reproductive factors and the risk of developing rheumatoid arthritis continue to report conflicting results, and the importance of these risk factors remains unresolved. Recent studies suggest that the protective effect is limited only to the development of definite rheumatoid arthritis with a more severe clinical course. Cross-sectional studies of diverse populations show consistent age- and gender-specific differences in the rates of hip fracture among persons of Japanese ancestry and rates among several different groups of whites in the United States. The results of a population-based longitudinal cohort study suggest that women who live in communities where the drinking water has a high content of fluoride have a greater risk of osteoporosis and subsequent fractures than those living in communities with low fluoride in the drinking water. Finally, several recent reports provide additional evidence of the increasing incidence of acute rheumatic fever in the United States and other parts of the world.

Adult↗
PubMed1992

Concordance between clinician and patient assessment of physical and mental health status.

The degree of concordance between clinicians' and patients' assessment of the patient's physical and mental functioning was examined in 166 consecutive eligible outpatients with rheumatoid arthritis (RA) using 4-category ordinal scales. The weighted kappa statistic was 0.39 for physical functioning and 0.30 for mental functioning, both indicating a fair degree of concordance. This disagreement differed in magnitude and direction depending on the level of disability present. We conclude that clinicians and their patients with RA often disagree in their assessment of the degree of physical and mental impairment that the patient experiences. These disagreements demonstrate the need for formal assessments of outcome and should be recognized and resolved when managing individual patients.

Adolescent↗
PubMed1992

The importance of incidence registries for connective tissue diseases.

There have been numerous studies conducted to determine the frequencies of CTD. These investigations, however, were usually not population based, relied on data sources set up primarily for administrative purposes, lacked unified methodologies for case definitions and verification, and failed to estimate the level of case ascertainment. Population based registries offer an alternative to past approaches and should not be overlooked for CTD. We propose that a standardized approach, as outlined above, will facilitate the development of registries and will permit the evaluation of the incidence of CTD across race, geographic area, and time. The establishment of standardized population based registries would form the foundation of a coordinated national and global effort to identify the etiology, and perhaps preventative measures, for these serious conditions.

Connective Tissue Diseases↗
PubMed1989

Lack of correlation between the Steinbrocker staging of hand radiographs and the functional health status of individuals with rheumatoid arthritis.

We evaluated the correlation between destructive changes seen on hand radiographs and disability in 54 patients with definite or classic rheumatoid arthritis. No statistically significant correlation was found between radiographic findings and patient disability as determined by patient and physician assessment or by the patient's score on the Arthritis Impact Measurement Scales questionnaire. These findings call into question the appropriateness of using hand radiographs as a determinant of disability or as a criterion for disability insurance benefits.

Adolescent↗
PubMed1988

A box-graph method for illustrating relative-size relationships in a 2 x 2 table.

The proportional relationships of the four numbers in a 2 x 2 table can be displayed using two types of box graphs. In one approach, a 'unitary square' is first divided according to the denominator proportions of the two groups formed in a cohort or case-control study, and then re-divided according to the numerator proportions in each group. In the second method, the numbers are arranged as four squares, proportionately sized according to the square root of each number, and contiguously adjacent to a central reference point. The methods offer a pictorial format for showing contingency counts in a manner analogous to the graphs used for other forms of data.

Data Interpretation, Statistical↗
PubMed1986

Rates of sensitivity reactions to aspirin: problems in interpreting the data.

This work was done to determine the reasons for variation in the reported rates--ranging from less than 1% to greater than 50%--of sensitivity to aspirin and cross-reactivity to acetaminophen and ibuprofen. In 47 studies that reported rates of sensitivity and in 23 reports that contained series of sensitive patients, we examined the research setting, source of patients, clinical attributes of the study group, admission process, and selection, operational definition, and method of determining sensitivity reactions. In five studies with reasonably well-specified methods, the reported sensitivity rates to aspirin were lowest (0.3% to 0.9%) for patients without allergic tendencies, higher in asthmatics, and highest if patients had nasal polyps or severe atopy. Although not determined in any of these studies, the rate of sensitivity in a general (nonclinical) population would doubtlessly be substantially lower than the rate of three per 1000 reported for nonallergic patients. The admixture of different clinical groups, varying definitions, and ascertainment of a sensitivity reaction seem to be responsible for the variations in the reported rates of sensitivity and cross-reactivity.

Acetaminophen↗
PubMedDate not supplied

Predicting discharge outcome after elective hip and knee arthroplasty.

The objective of this prospective study was to determine if differences exist between individuals who require an inpatient rehabilitation program after elective hip and knee arthroplasty from those patients who can be discharged directly home. Multiple variables consisting of baseline demographics, social status, insurance status, medical history, pain level, quantitative strength, range of motion, and functional ability were examined. The primary outcome measure was the discharge destination from the orthopedic service and consisted of either a discharge to home or a discharge to an inpatient rehabilitation unit. Of the 162 patients followed, 65 (40%) were discharged to an inpatient rehabilitation unit, whereas 97 were discharged to home. The patients discharged to inpatient rehabilitation tended to live alone, were significantly older (mean difference = 6.3 yr), and had increased comorbid conditions (p < 0.001 for all variables). Patients discharged to a rehabilitation unit reported significantly greater pain levels than those discharged to home (P < 0.001). The attainment of a supervision level of function demonstrated greater differences between groups than the attainment of independent function for all functional measures. A logistic regression model was developed that predicted 76% of the discharges to rehabilitation by the third physical therapy session postsurgery. In conclusion, predictive markers do exist that differentiate individuals who require further inpatient therapy services after joint replacement surgery.

Aged↗