Hospitals matched control

Hu (1991) examined the long-term consequences among survivors of childhood plumbism. Survivors consisted of children admitted to the Boston Children s Hospital from 1930 to 1944 for childhood plumbism. Matched controls (age, sex, and neighborhood) were enlisted through the use of town books. 

Olsson and Brandt (1980) carried out a hospital-based case-control study of Hodgkin s disease and chemical exposures in Lund, Sweden. Twenty-five consecutive male cases aged 20-65 years were included. Two neighbourhood-matched controls were selected for each case from the Swedish population register. Interviews with study subjects focused on their detailed job history, and in particular exposure to solvents. Interview data were supplemented with visits to employers in some cases. Four of the cases and none of the controls had been exposed to xylene. All exposed cases were also exposed to other solvents. [The Working Group noted the opportunity for information bias, since the interviewer was not blind to disease status or to the study objectives ]... 

Case-Control Studies. These are retrospective studies that enroll individuals with disease (cases) and without disease (controls) at the beginning of the study. The prevalence of the exposure of interest is then compared between the controls and the cases. Cases may be incident, which are new cases that are identified in a defined time period, or prevalent, which are all the cases that have occurred up to a certain point in time. Controls can be selected from the population (such as the same geographical region as cases) or from the same hospitals as the cases hospital controls are individuals who have disease other than the disease of interest. When using hospital-based controls, care should be taken not to select individuals with diseases that may share the same risk factors as the disease under study. To make subjects as comparable as possible, with the exception of the disease of interest, controls are often matched (either individually or by frequency) to the cases for age, sex, ethnicity, and other relevant variables. 

The results of a hospital-based case-control study in 121 patients with a first episode of central nervous demyelina-tion occurring within 180 days after either hepatitis B vaccine or other vaccines have been reported (37). The results were compared with age- and sex-matched controls seen during the same period. No conclusion regarding a causal relation between hepatitis B vaccine and a first MS episode could be drawn, but the authors were not able to exclude such an association with certainty. 

Two studies of the possible association between NSAIDs and the onset or exacerbation of inflammatory bowel disease have given contrasting results. In the first study (139) the authors interviewed 60 patients (mean age 42 years) with either Crohn s disease or ulcerative colitis who required admission to hospital owing to symptoms of their disease, and 62 matched controls (mean age 46 years) with irritable bowel syndrome who did not require hospitalization. Patients were asked about their use of NSAIDs and the relation in time and duration to the exacerbation or onset of the inflammatory bowel disease. There was an association with the use of NSAIDs in 31% of the patients with inflammatory bowel disease, but in only 2% of those with irritable bowel syndrome. Compared with patients with irritable bowel syndrome the odds ratio (OR) for an exacerbation or new onset of symptoms of inflammatory bowel disease after recent use of NSAIDs (defined as use within 1 month of symptom exacerbation or onset of disease) was 20 (95% Cl = 2.6, 160). 

A retrospective case-control study conducted by the same group who first identified a relation effect of pimozide and thioridazine on the QT interval (SEDA-24, 55) has been published (26). The study was carried out in five large psychiatric hospitals in England and included all inpatients with sudden unexplained death over a period of 12 years (1984-1995) and two controls for each case from the same hospital matched for age, sex, and duration of inpatient stay, one of whom was also matched for... 

Johnsen and coworkers [160] conducted another observational population-based case-control study to identify the risk of AMI in patients who used nonaspirin non-selective and COX-2 specific NSAIDs. Information for the study was collected from hospital discharge databases in Denmark and included 10, 280 cases of first-time hospitalization for AMI and 102, 797 matched controls without a history of AMI. Data was obtained for patients with a mean age of 69.6 years. There was a significantly higher incidence of serious cardiovascular events (AMI) in those whom were taking rofecoxib in comparison to subjects not taking NSAIDs (nonusers). Same observation was noted in the celecoxib, other COX-2 selective inhibitors, naproxen, and other non-selective NSAIDs groups, although to a lesser extent than for rofecoxib. In this study, celecoxib was associated with the lowest risk of AMI when compared to rofecoxib and the other non-selective NSAIDs. The authors concluded that caution should... 

Helin-SaLmivaara et al.[t 63] 2006 Population- First Ml requiring based, hospitalization matched case-control study 33309 cases and 138949 controls matched for age, sex, hospital catchment area Adjusted Odds Ratios among current users days 1-14 (study also assessed risk by proximity and category of latest prescription) Any NSAID 1.39 (1.23-1.58) Conventional (diclofenac ibuprofen, naproxen...) 1.37 (1.17-1.60) Semi-selective (etodolac, nabumetone, meloxicam) 1.56 (1.18-2.05) Cox-2 selective 1.32 (0.88-1.96) Increased, modest and similar risk of first-time Ml in patients taking conventional, semi-selective, and Cox-2 selective NSAIDs. 

The detailed case records of these 1000 were then analyzed quite independently by Dr. Frances Meuli, M.B., Ch.B. (Otago, New Zealand), who established their presentation date of untreatability by such conventional standards as the establishment of inoperability at laparotomy, the abandonment of any definitive form of anti-cancer treatment, or the final date of admission for terminal care. This presentation date of untreatability corresponds to the date when ascorbate supplementation was initiated in the treated group. Comparable survival times of the 10 matched controls could then be calculated. We accept that the presentation date of untreatability can be influenced by many factors in individual patients, but we contend that the use of 1(K)0 controls managed by the same clinicians in the same hospital over the last 10 years provides a sound basis for this comparative study. We record our thanks to Dr. Meuli for her unbiased and valuable contribution to this investigation. 

Macrolide antibiotics In a retrospective population-based nested case-control study from the National Health Insurance Research Database details of patients with heart failure newly treated with digoxin were retrieved from the database [b "]. Patients who were admitted to hospitals with a diagnosis of digoxin intoxication were identified and compared with matched controls. There were 154058 patients 595 were cases and 27020 matched controls were selected for comparison. Prescription of clarithromycin at 7, 14, and 30 days before the index date was associated with a increased rate of hospitalization for digoxin intoxication of three to five times. Clarithromycin in a prescribed daily dose (PDD)/defined daily dose (DDD) ratio >2 led to a 55-fold increase in risk. This study provides empirical evidence that interactions of digoxin with clarithromycin increases the risk of hospitalization for digoxin intoxication in patients with heart failure. 

Although tradition in some cultures attributes a cause and effect relationship between worms and xerophthalmia, the scientific evidence for more than mere coexistence is somewhat equivocal. Thirty percent of the subjects with Bitot s spots and active comeal disease recmited from a hospital based study in Indonesia, reported a history of passing worms within the past month, but when only comeal cases were compared with a matched control group, the differences in the prevalence of worms (24% and 18%, respectively) were not significantly different. In the countrywide xerophthalmia prevalence survey, significantly different prevalence rates were recorded for children with Bitot s spots (22%), their matched controls (14%), and all others (9%) (Sommer, 1982a). In the Philippines, Solon et aL (1978) did not find a difference in infestation rates between children with mild xerophthalmia and those without, but in Jordan a difference was reported. 

In another retrospective population-based case-control study, data from the National Health Insurance Research Database were scrutinized in a search for patients with heart failure newly treated with digoxin between January 2001 and December 2004 who were hospitalized for digitalis toxicity they were compared with the matched controls for use of clarithromycin [5 ]. Prescription of clarithromycin before the index date was associated with increased risk of hospitalization for digoxin intoxication the relative risks were 4.36 at 7 days (95% Cl = 1.28,15), 5.07 at 14 days (95% Cl = 2.36, 11), and 2.98 at 30 days (95% Cl = 1.59, 5.63). The effect was dose related. 

In 1981, Lawson et al.,87 for example, compared a group of 210 women hospitalized for fibrocystic disease with 241 women who had breast cancer and were drawn from two ongoing studies in different countries. They matched each case to three female control patients on age, current smoking habits, country, and study. Recent coffee and tea consumption in cases and controls were compared and were shown to have a modest positive association with hot beverage consumption for both fibrocystic disease and breast cancer, but there was no dose-response relationship. The risk of fibrocystic disease associated with heavy consumption of hot beverages (7+ cups per day) vs. none was elevated but not statistically significant. 

The clinical part of the study was conducted with participation of 116 adolescent patients aged from 10 to 18 years hospitalized by the Department of Pediatrics for examination and treatment of chronic dyspeptic complaints. The control group comprised 38 age matched healthy volunteers. The Regional Research Ethics Committee of Ukraine approved the study. 

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