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Biomedical subjects

J Gilchrist

Publications and source records attributed to J Gilchrist.

At least 19 recordsLinked to original sources

Non-fatal horse related injuries treated in emergency departments in the United States, 2001-2003.

OBJECTIVE: To characterise and provide nationally representative estimates of persons with non-fatal horse related injuries treated in American emergency departments. METHODS: The National Electronic Injury Surveillance System All Injury Program (NEISS-AIP) is a stratified probability sample comprising 66 hospitals. Data on injuries treated in these emergency departments are collected and reported. NEISS-AIP data on all types (horseback riding and otherwise) of non-fatal horse related injuries from 2001 to 2003 were analysed. RESULTS: An estimated 102,904 persons with non-fatal horse related injuries (35.7 per 100,000 population) were treated in American emergency departments each year from 2001 to 2003 inclusive. Non-fatal injury rates were higher for females (41.5 per 100,000) than for males (29.8 per 100,000). Most patients were injured while mounted on a horse (66.1%), commonly from falling or being thrown by the horse; while not mounted, injuries most often resulted from being kicked by the horse. The body parts most often injured were the head/neck region (23.2%), lower extremity (22.2%), and upper extremity (21.5%). The most common principal diagnoses were contusions/abrasions (31.4%) and fractures (25.2%). For each year that was studied, an estimated 11 502 people sustained traumatic brain injuries from horse related incidents. Overall, more than 11% of those injured were admitted to hospital. CONCLUSIONS: Horse related injuries are a public health concern not just for riders but for anyone in close contact with horses. Prevention programmes should target horseback riders and horse caregivers to promote helmet use and educate participants about horse behaviour, proper handling of horses, and safe riding practices.

Accident Prevention↗

Things that go beep: experience with an ED guideline for use of a handheld metal detector in the management of ingested non-hazardous metallic foreign bodies.

OBJECTIVES: To review compliance with our emergency department (ED) guideline on the imaging of ingested non-hazardous metallic foreign bodies in children, investigate adverse outcomes, and make suggestions for improving the guideline. METHODS: Retrospective analysis of patients presenting in a 3 year period to a paediatric ED with a history of possible metallic foreign body (MFB) ingestion, who were managed according to an ED guideline. RESULTS: We identified 430 episodes of possible MFB ingestion, of which 422 were eligible for inclusion in the study. Compliance with the guideline was 77.8% with no significant adverse events. The exclusion of symptoms as a criterion for x ray results in a reduction in the x ray rate of 56% in the symptomatic group with no increase in adverse events. CONCLUSION: A handheld metal detector (HMD) can be safely and reliably used in lieu of plain radiography to investigate children with a history of MFB ingestion, irrespective of symptoms and without incurring any significant adverse events.

Adolescent↗

Roller coaster related fatalities, United States, 1994--2004.

OBJECTIVE: To determine the number of fatalities related to roller coasters and examine factors common to multiple incidents. METHODS: A case was defined as the death of a person, which was associated with a roller coaster in the United States between 15 May 1994 and 14 May 2004. Cases were identified from four DATA SOURCES: (1) Consumer Product Safety Commission, (2) Lexis-Nexis, (3) Medline, and (4) Safer parks. RESULTS: Forty people, ranging in age from 7 to 77 years, were killed in 39 separate incidents. Twenty nine (73%) deaths occurred among roller coaster patrons. Eleven fatalities resulted from external causes related to injuries from falls or collisions. Eighteen people died from medical conditions that might have been caused or exacerbated by riding a roller coaster; 15 were the result of intracranial hemorrhages or cardiac problems. Eleven (28%) deaths involved employees; all were caused by injuries. CONCLUSIONS: Approximately four deaths annually in the United States are associated with roller coasters. Prevention of roller coaster fatalities is dependent on establishing an effective surveillance system for amusement ride injuries, engineering rides to better protect both patrons and employees, improving training and supervision of employees regarding safety precautions, and posting cautionary notices near roller coasters for people with specified medical conditions. Further research is needed on roller coaster related deaths resulting from intracranial hemorrhages and cardiac problems.

Accidents, Occupational↗

Localization of VGLUT3, the vesicular glutamate transporter type 3, in the rat brain.

We have recently identified a third subtype of glutamate vesicular transporter (VGLUT) named VGLUT3. In the present study, we provide a detailed account of the regional and cellular distributions of VGLUT3 in the rat brain, using specific nucleotide probes and antisera. The distribution of VGLUT3 protein was compared with that of the other vesicular transporters (VGLUT1 and VGLUT2). All the areas expressing VGLUT3 also contain high levels of VGLUT1 and -2 proteins, but, at a finer level of analysis, the distribution of the three subtypes differs. Unlike VGLUT1 and -2, VGLUT3 expression is limited to discrete cell populations. Neurons containing VGLUT3 transcript are essentially observed in the caudate-putamen, the olfactory tubercle, the nucleus accumbens, the hippocampus, the interpeduncular nucleus and the dorsal and medial raphe nuclei. More scattered populations of VGLUT3 expressing neurons are found in the cerebral cortex. The distribution of the VGLUT3 protein, as determined with specific antisera, overlaps with that of the transcript in the caudate-putamen, olfactory tubercles, hippocampus, cortex, interpeduncular nucleus, and raphe nuclei, suggesting that VGLUT3 is essentially present in local projection neurons in these regions. Microscopic examination reveals staining of terminals and perikarya. Furthermore, co-localization studies indicate that VGLUT3 is present in GABAergic interneurons in the hippocampus, as well as in the interpeduncular nucleus. However, other regions, such as the substantia nigra (pars compacta), the ventral tegmental area, and the parabigeminal nucleus, receive a dense VGLUT3 terminal labeling although they do not contain VGLUT3 expressing neurons. In these regions, VGLUT3 immunoreactivity may be present in terminals of long projecting neurons. This subclass of glutamatergic afferents differs from other "classical" excitatory terminals that express VGLUT1 or VGLUT2. The distribution of VGLUT3 in the rat brain suggests an unsuspected function of vesicular glutamate transport in subsets of interneurons and in neuromodulatory neurons.

Amino Acid Transport Systems, Acidic↗

Impact of age and duration on sight-threatening retinopathy in South Asians and Caucasians attending a diabetic clinic.

AIMS: To examine diabetic retinopathy in Asians and Caucasians attending a hospital diabetic clinic and to evaluate the impact of the significant risk factors on the probability of sight-threatening retinopathy. METHODS: A total of 500 diabetic patients (268 Asians, 232 Caucasians) who attended a diabetic clinic within a defined time period were examined for severity of diabetic retinopathy. The existence of sight-threatening retinopathy (STR) was compared in the two groups. Significant risk factors such as age, duration and hypertension were analysed against the probability of STR in each of the two races. RESULTS: Asians demonstrated significantly higher rates of STR. Univariate analysis showed age, duration, race, gender, and insulin-requiring status to be significantly associated with STR. Multivariate logistic regression showed a significant association of STR with race, age and duration of diabetes, with no significant interaction effects between variables. The logistic regression model predicted STR in Asians to be matched to that in Caucasians by a 12.5-year difference factor; that is, Caucasians were older by 12.5 years or had a 12.5-year longer duration than Asians for the same level of STR. CONCLUSIONS: After adjusting for age and duration of diabetes, the probability of STR in Asian diabetic patients attending the diabetic clinics in Bradford is significantly higher than that in Caucasians (odds ratio=3.184, P<0.05). The impact of age and duration was significantly higher in patients of South Asian origin compared to Caucasians.

Adult↗

Injuries from paintball game related activities in the United States, 1997-2001.

OBJECTIVE: To quantify and characterize injuries resulting from paintball game related activities among persons >/=7 years in the United States. SETTING: Hospitals included in the National Electronic Injury Surveillance System (NEISS); these are composed of a stratified probability sample of all hospitals in the United States with emergency departments. METHODS: Using NEISS, non-fatal injury data for paintball game related injury cases from 1997-2001 were obtained from emergency department records. Participation estimates used to calculate injury rates were obtained from a yearly survey funded by the National Sporting Goods Association. RESULTS: An estimated 11 998 persons >/=7 years with paintball game related injuries were treated in emergency departments from 1997-2001, with an annual average rate of 4.5 per 10 000 participants (95% confidence interval 3.3 to 5.7). The paintball game related injury rate was highest for 18-24 year olds (4.9 per 10 000 participants) and most injuries (94.0%) occurred among males. Almost 60% of all injured persons >/=7 years were treated for paintball pellet wounds of which most were to the eye. While 76.9% of injured persons ages 7-17 years were treated for paintball pellet wounds, almost 40% of those >/=18 years were treated for injuries resulting from overexertion or a fall. Lower extremity injuries were also common (23.0%), mostly from overexertion. Most injured persons (95.5%) were treated and released. CONCLUSIONS: As paintball games become more popular, efforts are needed to increase training, enforce rules, and educate participants about how to stay safe, such as wearing protective eye gear, when engaged in paintball games at home, in a public area, or in a sports field.

Accidental Falls↗

Sports and recreation related injury episodes in the US population, 1997-99.

OBJECTIVE: To characterize sports and recreation related (SR) injury episodes in the US population. SR activities are growing in popularity suggesting the need for increased awareness of SR injuries as a public health concern for physically active persons of all ages in the US population. SETTING: The National Health Interview Survey (NHIS) is a face-to-face household survey conducted yearly by the National Center for Health Statistics, part of the Centers for Disease Control and Prevention. Demographic and health data are collected from a nationally representative sample of the civilian, non-institutionalized population residing in the US. METHODS: Medically attended injury events reported in the 1997-99 Injury Section of the NHIS were categorized according to the associated sport or recreational activity using a classification scheme based on the International Classification of External Causes of Injury system. Episodes where the injured person received any type of medical attention (that is, medical advice or treatment) from any health care provider were used to report the incidence, severity, and nature of SR injuries sustained by US citizens. RESULTS: Annually, an estimated seven million Americans received medical attention for SR injuries (25.9 injury episodes per 1000 population). For 5-24 year olds, this national estimate was about 42% higher than estimates based on SR injuries seen only in emergency departments over a similar time frame. The highest average annual SR injury episode rates were for children ages 5-14 years (59.3 per 1000 persons) and persons aged 15-24 years (56.4 per 1000 persons). The SR injury episode rate for males was more than twice the rate for females. The age adjusted injury rate for whites was 1.5 times higher than for blacks (28.8 v 19.0 per 1000 population). Basketball was the most frequently mentioned SR activity when the injury episode occurred, with a rate of about four injury events per 1000 population. Strains and sprains accounted for 31% of injury episodes. An estimated 1.1 million SR episode related injuries involve the head or neck region, of which 17% were internal head injuries. The most common mechanisms of injury were struck by/against (34%), fall (28%), and overexertion (13%). CONCLUSION: As physical activity continues to be promoted as part of a healthy lifestyle, SR injuries are becoming an important public health concern for both children and adults. Prevention efforts aimed at reducing SR injuries through targeting high risk activities, places of occurrence, activity, risk behaviors, and use of protective devices need to go beyond focusing on children and also consider physically active adults.

Adolescent↗

Differential ranking of causes of fatal versus non-fatal injuries among US children.

OBJECTIVE: Leading causes of fatal and non-fatal injury among US children aged <15 years were compared. METHOD: A descriptive study was conducted using nationally representative data on injury related deaths (National Vital Statistics System) and on non-fatal injury related emergency department visits (IEDV; National Electronic Injury Surveillance System-All Injury Program). Data were accessed using a publicly available web based system. RESULTS: Annually, an estimated 7100000 pediatric IEDV and 7400 injury deaths occurred. The overall non-fatal to fatal ratio (NF:F) was 966 IEDV:1 death. Among deaths, the leading causes were motor vehicle traffic occupants (n = 1700; NF:F = 150:1), suffocations (n = 1037; NF:F = 14:1), and drownings (n = 971, NF:F = 6:1). Among non-fatal injuries, falls (estimated 2400000) and struck by/against (estimated 1800000) were the most common causes, but substantially less lethal (NF:F = 19000:1 and 15000:1, respectively). CONCLUSIONS: The leading causes of pediatric fatal and non-fatal injuries differed substantially. This study indicates the need for consideration of common causes of non-fatal injury, especially falls.

Accidental Falls↗

Prevention of knee injuries in sports. A systematic review of the literature.

AIM: We reviewed evidence regarding risk factors associated with incidence of knee injuries both to assess the effectiveness of prevention strategies, and to offer evidence-based recommendations to physicians, coaches, trainers, athletes, and researchers. METHODS: We searched electronic data bases without language restriction for the years 1966 - September 1, 2001, identified citations from reference sections of research papers retrieved, contacted experts in the field, and searched the Cochrane Collaboration. Of the 328 citations identified, we emphasized the results from the 13 reports that compared alternative methods to prevent knee injury and assessed the methodologic quality of these reports using a standardized instrument. RESULTS: Five studies addressed the effectiveness of bracing in football players; these studies showed no consistent evidence of benefit. Two studies comparing alternative cleat designs and a controlled study testing the effects of adjustments in the ski boot/binding system were difficult to interpret because of inadequate reporting of methodology. Six prospective studies that addressed the impact of conditioning and training showed promise of proprioception and neuromuscular training for protection against knee injury. We identified serious flaws in study design, control of bias, and statistical methods; the median quality scores ranged from 11 to 56 (out of 100). CONCLUSION: Structured training programs that emphasize neuromuscular and proprioceptive training offer encouraging evidence for the prevention of knee injuries. However, flaws in study design and implementation have limited the effectiveness of work in this field. A rigorously implemented research program is needed to address this critically important sports medicine problem.

Athletic Injuries↗

Breeds of dogs involved in fatal human attacks in the United States between 1979 and 1998.

OBJECTIVE: To summarize breeds of dogs involved in fatal human attacks during a 20-year period and to assess policy implications. ANIMALS: Dogs for which breed was reported involved in attacks on humans between 1979 and 1998 that resulted in human dog bite-related fatalities (DBRF). PROCEDURE: Data for human DBRF identified previously for the period of 1979 through 1996 were combined with human DBRF newly identified for 1997 and 1998. Human DBRF were identified by searching news accounts and by use of The Humane Society of the United States' registry databank. RESULTS: During 1997 and 1998, at least 27 people died of dog bite attacks (18 in 1997 and 9 in 1998). At least 25 breeds of dogs have been involved in 238 human DBRF during the past 20 years. Pit bull-type dogs and Rottweilers were involved in more than half of these deaths. Of 227 reports with relevant data, 55 (24%) human deaths involved unrestrained dogs off their owners' property, 133 (58%) involved unrestrained dogs on their owners' property, 38 (17%) involved restrained dogs on their owners' property, and 1 (< 1%) involved a restrained dog off its owner's property. CONCLUSIONS: Although fatal attacks on humans appear to be a breed-specific problem (pit bull-type dogs and Rottweilers), other breeds may bite and cause fatalities at higher rates. Because of difficulties inherent in determining a dog's breed with certainty, enforcement of breed-specific ordinances raises constitutional and practical issues. Fatal attacks represent a small proportion of dog bite injuries to humans and, therefore, should not be the primary factor driving public policy concerning dangerous dogs. Many practical alternatives to breed-specific ordinances exist and hold promise for prevention of dog bites.

Animals↗

Exercise-related injuries among women: strategies for prevention from civilian and military studies.

SCOPE OF THE PROBLEM: The numerous health benefits of physical activity have been well documented, resulting in public health support of regular physical activity and exercise. Although beneficial, exercise also has corresponding risks, including musculoskeletal injuries. The incidence and risk factors for exercise-related injury have been poorly assessed in women. Many civilian exercise activities (e.g., jogging, walking, and erobics) have corollaries in military physical training; injury incidence and risk factors associated with military physical training have been more thoroughly studied. ETIOLOGIC FACTORS: Injury risks increase as the amount of training increases (increased xposure). The same exercise parameters that can be modified to enhance physical fitness (i.e., frequency, duration, and intensity) also influence the risk for injury in a dose-response manner. Higher levels of current physical fitness (aerobic fitness) protect the participant against future injury. A history of previous injury is a risk factor for future injury. Smoking cigarettes has been associated with increased risk for exercise-related injury. Studies conducted in military populations suggest that the most important risk factor for injuries among persons engaged in vigorous weight-bearing aerobic physical activity might be low aerobic fitness rather than female sex. RECOMMENDATIONS FOR PREVENTION: Because of the limited scientific research regarding women engaging in exercise, general recommendations are provided. Women starting exercise programs should be realistic about their goals and start slowly at frequency, duration, and intensity levels commensurate with their current physical fitness condition. Women should be informed about the early indicators of potential injury. Women who have sustained an injury should take precautions to prevent reinjury (e.g., ensuring appropriate recovery and rehabilitation). RESEARCH AGENDA: In general, a combination of factors affects the risk for exercise-related injury in women. How these factors act singly and in combination to influence injury risk is not well understood. Additional research regarding exercise-related injury in women is needed to answer many of the remaining epidemiologic questions and to help develop exercise programs that improve health while reducing the risk for injury. CONCLUSION: Exercise is an important component in improving and maintaining health; however, injury is also an accompanying risk. A review of key military and civilian research studies regarding exercise-related injuries provides some clues to reducing these injuries in women. Greater adherence to exercise guidelines can help decrease these risks.

Athletic Injuries↗

Injury prevention practices as depicted in G-rated and PG-rated movies.

BACKGROUND: Previous studies on alcohol, tobacco, and violence suggest that children's behavior can be influenced by mass media; however, little is known about the effect of media on unintentional injuries, the leading cause of death among young persons in the United States. OBJECTIVE: To determine how injury prevention practices are depicted in G-rated (general audience) and PG-rated (parental guidance recommended) movies. DESIGN: Observational study. SETTING: The 25 movies with the highest domestic box-office grosses and a rating of G or PG for each year from 1995 through 1997. Movies that were predominantly animated or not set in the present day were excluded from analysis. SUBJECTS: Movie characters with speaking roles. MAIN OUTCOME MEASURES: Safety belt use by motor vehicle occupants, use of a crosswalk and looking both ways by pedestrians crossing a street, helmet use by bicyclists, personal flotation device use by boaters, and selected other injury prevention practices. RESULTS: Fifty nonanimated movies set in the present day were included in the study. A total of 753 person-scenes involving riding in a motor vehicle, crossing the street, bicycling, and boating were shown (median, 13.5 person-scenes per movie). Forty-two person-scenes (6%) involved falls or crashes, which resulted in 4 injuries and 2 deaths. Overall, 119 (27%) of 447 motor vehicle occupants wore safety belts, 20 (18%) of 109 pedestrians looked both ways before crossing the street and 25 (16%) of 160 used a crosswalk, 4 (6%) of 64 bicyclists wore helmets, and 14 (17%) of 82 boaters wore personal flotation devices. CONCLUSIONS: In scenes depicting everyday life in popular movies likely to be seen by children, characters were infrequently portrayed practicing recommended safe behaviors. The consequences of unsafe behaviors were rarely shown. The entertainment industry should improve its depiction of injury prevention practices in G-rated and PG-rated movies.

Accidents, Traffic↗

Cognitive-behaviour therapy as a treatment for irritable bowel syndrome: a pilot study.

OBJECTIVE: The irritable bowel syndrome (IBS) is a chronic and often disabling functional bowel disorder. Psychological treatments, in particular cognitive and behavioural interventions, have been shown to be effective for this disorder. The aim of this study was to test the efficacy of a cognitive-behaviour program. METHOD: Eight participants (seven female, one male) aged between 24 and 71 years, with a diagnosis of IBS according to the Rome criteria, were recruited from among the gastroenterology outpatients at Nepean Hospital, in Sydney, Australia. Participants were administered pretreatment on measures of psychological function and bowel symptom severity. Following a 2-week baseline period, participants began a structured psychological treatment comprising eight sessions of cognitive-behaviour therapy. Throughout treatment, participants maintained daily records of symptom severity and completed homework assignments to ensure treatment compliance. The pretreatment assessment measures were repeated 1 week post-treatment. RESULTS: After treatment, five of the eight patients no longer met the Rome diagnostic criteria for IBS. There was no significant reduction in bowel symptom frequency. There were, however, significant improvements in the distress and disability associated with bowel symptoms. Anxiety and depression were also significantly reduced. CONCLUSIONS: Cognitive-behaviour therapy reduced the distress and disability associated with IBS, but not the frequency of bowel symptoms. This supports the proposed cognitive model for IBS, and cognitive-behaviour therapy appears to have its effect by altering the cognitive response to visceral hypersensitivity.

Adult↗

Merkel cell carcinoma of the skin.

BACKGROUND: Neuroendocrine/Merkel cell carcinoma (MCC) of the skin is an uncommon tumour. Currently, there are only limited data available on the natural history, prognostic factors, and patient management of MCC. OBJECTIVES: To review our experience and build the largest database from the literature. METHODS: Twenty-eight cases from the London Regional Cancer Center were combined with 633 cases obtained from the literature searched in English, French, German, and Chinese for the years 1966 to 1998. The database included age, sex, initial disease status at presentation to the clinic, site of primary, any coexisting disease, any previous irradiation, sizes of primary/nodal/distant metastases, management details, and final disease status. A new modified staging system was used: stage Ia (primary disease only, size > 2 cm), stage Ib (primary disease only, size > 2 cm); stage II (regional nodal disease), and stage III (beyond regional nodes and/or distant disease). RESULTS: Age > 65 years, male sex, size of primary > 2 cm, truncal site, nodal/distant disease at presentation, and duration of disease before presentation (< or =3 months) were poor prognostic factors. Surgery was the initial treatment of choice and it significantly improved overall survival (p =.004). CONCLUSIONS: We identified poor prognostic factors that may necessitate more aggressive treatment. The suggested staging system, incorporating primary tumour size, accurately predicted outcomes.

Aged↗

Chemotherapy in neuroendocrine/Merkel cell carcinoma of the skin: case series and review of 204 cases.

PURPOSE: To study the use of chemotherapy for Merkel cell carcinoma (MCC) of the skin. PATIENTS AND METHODS: Twenty-five cases of MCC were treated at the London Regional Cancer Center between 1987 and 1997. Thirteen cases treated with chemotherapy were reviewed with 191 cases from the literature. RESULTS: At presentation, 24 patients had localized skin lesions (stage I) and one had locoregional involvement (stage II). Among the nine cases with recurrent nodal disease, six had chemotherapy as a component of salvage treatment. They were all free of disease at a median of 19 months (range, 12 to 37 months). In contrast, two patients who had salvage radiotherapy alone died of disease. Overall survival (OS) and disease-free survival (DFS) were 59% and 43%, respectively, at two years. Median OS and DFS were 29 months (range, 1 to 133 months) and 9 months (range, 1 to 133 months), respectively. Nodal disease developed in 12 (50%) of 24 patients with stage I disease, and distant metastases developed in six (25%) of 24. Including those from the literature, there were 204 cases treated with chemotherapy. Cyclophosphamide/doxorubicin (or epirubicin)/vincristine combination +/- prednisone was the most commonly used chemotherapy regimen (47 cases), with an overall response rate of 75.7% (35.1% complete, 35. 1% partial, and 5.4% minor responses). Etoposide/cisplatin (or carboplatin) was the next most commonly used regimen (27 cases), with an overall response rate of 60% (36% complete and 24% partial responses). The difference in response rate was not statistically significant (P =.19). Among the 204 cases, there were seven (3.4%) toxic deaths. CONCLUSION: Chemoradiation for locally recurrent or advanced disease may be an option for patients with a good performance status.

Aged↗

Police enforcement as part of a comprehensive bicycle helmet program.

BACKGROUND: Bicycle-related head injuries cause >150 deaths and 45 000 nonfatal injuries among children in the United States annually. Although bicycle helmets are highly effective against head injury, only 24% of US children regularly wear one. Georgia mandated bicycle helmet use for children, effective July 1993. During that summer, 1 rural Georgia community passed an ordinance instructing police officers to impound the bicycle of any unhelmeted child. We evaluated the effect of active police enforcement of this ordinance, combined with a helmet giveaway and education program. METHODS: During April 1997, approximately 580 children in kindergarten through grade 7 received free helmets, fitting instructions, and safety education. Police then began impounding bicycles of unhelmeted children. We conducted an observational study, unobtrusively observing helmet use just before helmet distribution, several times during the next 5 months, and once 2 years later. RESULTS: Before the program began, none of 97 observed riders wore a helmet. During the next 5 months, helmet use among 358 observed children averaged 45% (range: 30%-71%), a significant increase in all race and gender groups. In contrast, adult use did not change significantly. Police impounded 167 bicycles during the study, an average of 1 per day. Two years after program initiation, 21 of 39 child riders (54%) were observed wearing a helmet. CONCLUSIONS: Without enforcement, the state and local laws did not prompt helmet use in this community, yet active police enforcement, coupled with helmet giveaways and education, was effective and lasting.

Adolescent↗

Optometric glaucoma referrals--measures of effectiveness and implications for screening strategy.

The effectiveness of disease screening is conventionally evaluated using the epidemiological indices of sensitivity and specificity, which measure the association between screening test results and final diagnoses of all the patients screened. The effectiveness of optometric glaucoma referrals cannot be measured using such indices because diagnoses are obtained only on patients who are referred, while the true disease status of those not referred remains unknown. Instead, glaucoma referral effectiveness has been evaluated using measures of 'detection rate'--the proportion of those screened who are correctly referred, and 'referral accuracy'--the proportion of those referred who are correctly referred occurrence. Examination of these operational measures shows that their obtainable values and, hence, their interpretation are influenced by the total proportions of diseased and referred patients, one or both of which will generally be unavailable in evaluating samples of referrals. On the other hand, if valid estimates of these proportions can be obtained from other sources, it is possible to rescale detection rate and referral accuracy to take account of them. This rescaling produces a pair of weighted kappa coefficients, chance-corrected measures of association between referral and diagnosis, which provide a better indication of true referral effectiveness than other measures. An important consequence of this approach is that it provides a clear quantitative illustration of the need for a dual strategy to improve the overall quality of optometric glaucoma screening; widespread adoption of more comprehensive modes of screening to improve accuracy, together with a significant increase in the total numbers of patients screened to improve detection. In order for detection rates to reach desirable levels, the total number of referrals in any sub-population of patients must match or exceed the number of patients with disease. This analysis confirms quantitatively that which is intuitively obvious; not only that glaucoma awareness and uptake of screening opportunities must be encouraged in all patients over 40 years of age, but also that the older and/or more at risk patients are, the greater is their need to take advantage of glaucoma screening.

Glaucoma↗