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Biomedical subjects

K W Cross

Publications and source records attributed to K W Cross.

At least 19 recordsLinked to original sources
PubMed2005

Respiratory illness associated with influenza and respiratory syncytial virus infection.

AIMS: To estimate excess morbidity during periods of influenza and respiratory syncytial virus (RSV) activity. METHODS: Retrospective analysis of a sentinel practice network database in active and non-active virus periods. MAIN OUTCOME MEASURES: clinical diagnoses of new episodes of influenza-like illness (ILI), acute bronchitis, asthma, and otitis media. RESULTS: The clinical diagnosis of ILI was consistent with influenza virus activity and acute bronchitis with RSV. During periods of virus activity, estimates of excess morbidity in children aged 1-4 and 5-14 years diagnosed as having acute otitis media exceeded those diagnosed with each of the other three conditions; in children <1 year estimates for acute bronchitis were highest. Using a broad definition of virus activity and summarising the data for all children diagnosed with ILI, 60% was attributable to influenza (40% RSV) as were 37% of episodes diagnosed as acute bronchitis, 9% of those with asthma and 48% of those with otitis media. Using a narrow definition, corresponding proportions were: for ILI diagnoses 77% (23% RSV), acute bronchitis 32%, asthma zero, and otitis media 45%. Acute bronchitis was diagnosed twice as frequently in association with RSV as with influenza in all age groups: excess asthma episodes were only evident in RSV active periods. CONCLUSIONS: Except in relation to ILI, RSV caused more illness than the influenza virus in the respiratory diagnoses examined, emphasising the need for RSV prevention and treatment. Influenza was not associated with excess asthma episodes.

Acute Disease↗
PubMed2005

Influenza and its relationship to circulatory disorders.

Three sources of data (general practice episode data from the Weekly Returns Service of the Royal College of General Practitioners, national hospital admission data for England and national mortality data by date of death) were examined separately in each winter (1994/1995 to 1999/2000) to investigate the impact of influenza on circulatory disease. Weekly data on incidence (clinical new episodes) hospital emergency admissions and deaths certified to circulatory disorders and to respiratory diseases (chapters VII and VIII of ICD9) during influenza epidemic periods (defined from combined clinical/virological surveillance) were examined in age groups 45-64, 65-74 and > or =75 years. Data collected in the four winters in which there were substantial influenza A epidemics were consolidated for the period 6 weeks before to 6 weeks after each peak of the epidemic, and associations between the variables at different time lags examined by calculating cross-correlation coefficients. We also examined deaths due to ischaemic heart disease (IHD) as a proportion of all circulatory deaths and deaths due to influenza/pneumonia as a proportion of all respiratory deaths. There were no increases of GP episodes nor of emergency admissions for circulatory disorders in any of the three age groups during epidemic periods. Increased circulatory deaths occurred in all age groups and particularly in the oldest group. The large cross-correlation coefficients of deaths (circulatory and respiratory) with GP respiratory episodes at weekly lags of 0, -1 and 1 were evidence that the deaths and episode distributions were contemporaneous. The ratios of excess circulatory deaths relative to excess respiratory deaths during epidemic periods were 0.74 (age 45-64), 0.72 (65-74) and 0.57 (> or =75 years). Increased circulatory deaths contemporary with new incident cases of respiratory episodes but with no concomitant increase in admissions suggests rapid death during the acute phase of illness. Influenza contingency planning needs to take account of these deaths in determining policy for prophylaxis and in providing facilities for cardio-respiratory resuscitation.

Adolescent↗
PubMed2005

The incidence of molluscum contagiosum, scabies and lichen planus.

We aimed to describe the incidence of new episodes of molluscum contagiosum, scabies and lichen planus presenting to general practitioners in England and Wales. We examined data collected in a sentinel practice network (the Weekly Returns Service of the Royal College of General Practitioners) in which about half a million persons were observed each year over the period 1994-2003. The incidence of molluscum contagiosum in males was 243/100,000 person-years and in females 231; of scabies, males 351, females 437; of lichen planus, males 32, females 37. Incidence varied by year and age. Ninety per cent of molluscum contagiosum episodes were reported in children aged 0-14 years, where incidence in 2000 (midpoint of a 6-year period of stable incidence) was 1265/100,000 (95% CI 1240-1290). Scabies affected all ages and annual incidence ranged between 233 (95% CI 220-246) in 2003 and 470 (95% CI 452-488) in 2000. Lichen planus occurred chiefly in persons aged over 45 years: incidence (all ages) ranged between 27 (95% CI 23-31) in 2003 and 43 (95% CI 37-49) in 1998. The relative risk of female to male incidence (all ages) of molluscum contagiosum was 0.95 (95% CI 0.91-0.99); of scabies 1.25 (95% CI 1.21-1.28); and of lichen planus 1.19 (95% CI 1.08-1.13).

Adolescent↗
PubMed2004

Gender difference in the incidence of shingles.

We investigated age- and gender-specific incidence of shingles reported in a large sentinel practice network monitoring a defined population over the years 1994-2001. In total, 5915 male and 8617 female incident cases were studied. For each age group, we calculated the relative risk of females to males presenting with shingles. Incidence rates of chickenpox and herpes simplex were examined similarly. Shingles incidence was greater in females in each age group (except for 15-24 years). Relative risks (female to male) were greatest in age groups 45-64 years (1.48) and 0-14 years (1.43). There were no gender differences in the incidence of chickenpox except in the 15-24 years age group (female excess): for herpes simplex there were female excesses in all age groups. Gender-specific age-standardized incidence rates of shingles were calculated for each year and showed a consistent female excess in each of the 8 years (average annual excess 28%).

Adolescent↗
PubMed2000

Declining incidence of episodes of asthma: a study of trends in new episodes presenting to general practitioners in the period 1989-98.

BACKGROUND: A study was undertaken to determine trends in the incidence of new episodes of asthma presented to general practitioners participating in the Weekly Returns Service of the Royal College of General Practitioners, comprising 92 practices with a registered population of approximately 680 000 persons well distributed throughout England and Wales. These practices monitor the morbidity presented at every consultation, distinguishing between new episodes of illness and ongoing consultations. METHODS: Age specific weekly rates of new episodes of asthma (and of acute bronchitis) presenting to the general practitioners over the years 1989-98 were examined in four week blocks and analysed by multiple regression, separating secular from seasonal trends. RESULTS: Quadratic trends in episodes of asthma were evident in each of the age groups with peaks in 1993/4. Corresponding analyses for acute bronchitis disclosed similar trends generally peaking in the winter of 1993/4. Mean weekly incidence data (all ages combined) decreased in all quarters since 1993. Regional analysis (North/Central/South) showed similar decreases. CONCLUSIONS: There has been a gradual decrease in the incidence of asthma episodes and of acute bronchitis presenting to general practitioners since 1993. The trend of an increase before 1993 followed by a decrease cannot be explained by changes in the patterns of health care usage or diagnostic preference of doctors.

Adolescent↗
PubMed2000

Comparison of the seasonal patterns of asthma identified in general practitioner episodes, hospital admissions, and deaths.

BACKGROUND: Seasonal variations in asthma are widely recognised. This study was undertaken to investigate the relative differences in seasonal patterns by age as they impact on episodes of care in general practice, hospital admissions, and deaths. METHODS: General practice episode data from the Weekly Returns Service of the Royal College of General Practitioners, hospital admissions for asthma in England, and deaths registered as due to asthma in England and Wales over the years 1990-7 were examined. Age specific weekly rates of new episodes of asthma presenting to general practitioners, numbers of hospital admissions and deaths were analysed by the multiplicative decomposition method to separate secular from seasonal trends. The seasonal indices thereby obtained were plotted as three week moving averages. RESULTS: In children aged 0-4 and 5-14 years general practice episodes and admissions to hospital were strikingly congruent in timing and in magnitude, except in September when particularly high rates of admission (absolute and relative to general practice episodes) occurred. In the 15-44 age group there were marked mid summer peaks of general practice episodes and deaths but admissions to hospital were at about the annual average; in September/October there were peaks of episodes and admissions whereas deaths peaked in November. In the 45-64 age group a peak in general practice episodes of asthma was evident in mid summer when admissions were about average and deaths were at a minimum; all three measures tended to increase gradually with the approach of winter. Finally, in those age over 65 years, general practice episodes of asthma, admissions to hospital, and deaths followed similar 'U' shaped patterns with substantial peaks in mid winter. CONCLUSIONS: The seasonal pattern of asthma evolves with age. There are important differences in the seasonal pattern of general practice episodes, admissions to hospital, and deaths. Individual seasonal histories are important for the management of asthma. The combined analysis of these three data sets provides a new perspective on the epidemiology of asthma.

Adolescent↗
PubMed1996

Causes of death associated with psychiatric illness.

BACKGROUND: A prospective cohort analysis of mortality, among entrants to a population-based psychiatric case register, was undertaken to identify specific causes of death responsible for the increased risk of mortality previously reported in this large group of unselected patients. METHODS: The analysis was based on a study population of 16,871 cases, aged 15-89 years, from Worcester and Kidderminster Health Districts, entering the case register between 1974 and 1984 and generating a total of 85,073 patient-years (PYR) of observation. The underlying cause of death was coded to the relevant revision of the International Classification of Diseases (ICD). Numbers of deaths observed in the study population were compared with the number of deaths expected on the basis of mortality rates for England and Wales. Comparisons were made for eight main causes of death, aggregated at Chapter level of the ICD, and 11 categories of psychiatric diagnoses. Two indices of mortality were used for evaluation: relative risk (RR) = observed deaths/expected deaths; and excess mortality rate (EMR) = (observed-expected deaths)/PYR. RESULTS: RRs were significantly raised for accidents, including suicides, as anticipated, and for various main causes of death. The increased risk of accidental death was found across the majority of the 11 psychiatric diagnostic groups although the EMRs were low at less than 5/1000 PYR. Deaths from respiratory disorders gave rise to the highest RRs after accidental deaths, and were responsible for substantial excess mortality among in-patients and patients with psychotic illnesses (especially dementia). The largest numbers of deaths of both sexes were due to diseases of the circulatory system, with a 40 per cent excess of observed over expected values in the whole series. The excess was due mainly to deaths of in-patients and of patients with psychotic diagnoses. No excess of deaths owing to neoplasms was found for either in-patients or out-patient groups. CONCLUSIONS: The findings that psychiatric illness is associated with an increased risk of death from "natural' causes and that the level of risk was related to the severity and to the diagnostic category of the illness have implications for patterns of care and use of resources.

Adolescent↗
PubMed1995

Concurrence of monthly variations of mortality related to underlying cause in Europe.

STUDY OBJECTIVE: The study aimed to examine the concurrence in the variation of monthly numbers of deaths in summer and winter from the four main underlying causes - respiratory, circulatory, neoplastic, and all others - in four countries. In particular, the hypothesis that most non-respiratory concurrent deaths are miscoded respiratory deaths and that a large proportion of the winter mortality currently attributed to circulatory disorders should be attributed to respiratory causes was considered. DESIGN: Mortality data were analysed graphically in relation to cause. Each of the four series of monthly data underwent time series analysis to remove auto-correlation, seasonality, and secular trends. Associations between paired causes of death and between multiple series (using Kendall's coefficient of concordance) were then examined after modelling. SETTING: Monthly deaths (65 years and over) related to underlying cause were examined for England and Wales (nine years), The Netherlands (nine years), Denmark (10 years), and Portugal (10 years - all ages). Weekly data for England and Wales (51 weeks) were also analysed. MAIN RESULTS: All combinations of monthly deaths related to underlying cause were strongly associated in all four countries. This concurrence was evident down to the lowest monthly values so that all seasonally related deaths above the minimum monthly value can be used as an estimate of the "concurrent" proportion. Associations involving deaths from neoplasm were weakest. Concurrence was evident even on a weekly analysis (England and Wales). Concurrent deaths in England and Wales accounted for 31.1% of respiratory, 16.0% of circulatory, 3.5% of neoplastic, 14.1% of deaths from other causes and 14.2% for all deaths combined. The equivalent percentages for concurrent deaths from all causes were 8.4% in the Netherlands, 9.3% in Denmark, and 16.8% in Portugal. CONCLUSIONS: Concurrence, which was present in each of the underlying causal groups in each of the four national data sets examined, suggests a common cause separate from the underlying cause that has been used in the presentation of mortality statistics. If the person concerned had not died at that time, as a result of this cause, he would not have died from the recorded underlying cause. Most of these non-respiratory concurrent deaths are miscoded. As a consequence, a large proportion of winter mortality currently attributed to circulatory disorders should be attributed to other causes, probably respiratory. More intensive research into the contribution made by acute respiratory diseases is proposed. The proportion of concurrent deaths varied in the four countries thereby limiting the validity of simple comparisons of national mortality statistics.

Adolescent↗
PubMed1993

Respiratory illness and mortality in England and Wales. A study of the relationships between weekly data for the incidence of respiratory disease presenting to general practitioners, and registered deaths.

The possible relationship between the incidence of respiratory diseases as reported to general practitioners and numbers of registered deaths in England and Wales has been examined. Morbidity data from sentinel practices for the period 1986-1990 (population covered increased from 220,000 to 470,000) were used to calculate weekly rates of aggregated respiratory disease for persons of all ages and for elderly persons (aged 65 years and over). The elderly respiratory disease rates and numbers of deaths were aggregated into 4-week periods; secular and seasonal trends were removed from each series and the two sets of residuals were examined graphically and cross correlation coefficients calculated. There was a very strong positive association between the respiratory disease rate and number of deaths in the same 4-week period and there was also a significant but less pronounced association between respiratory disease in one 4-week period and deaths in the next. After prior separation of weeks according to temperature into four bands, weekly rates for respiratory disease were also strongly associated with the number of weekly deaths for each temperature band. The synchronisation of peaks and troughs in the two series throughout the year supports the hypothesis that a cause and effect relationship exists between respiratory disease in the elderly and number of deaths. Other climatic and meteorological variables besides temperature may play a part in determining the spread of a respiratory disease. There is a for further research to identify the micro-organisms responsible for acute respiratory infections in the elderly.

Acute Disease↗
PubMed1993

Thyroxine prescription in the community: serum thyroid stimulating hormone level assays as an indicator of undertreatment or overtreatment.

Examination of thyroxine usage in a study in the United States of America revealed that many patients were prescribed thyroxine for non-thyroid indications, such as obesity and fatigue. Many of those receiving thyroxine had high or low serum thyroid stimulating hormone levels, indicating prescription of incorrect doses or lack of patient compliance with therapy. Long term thyroxine therapy may have effects upon the risk of osteoporosis. The aims of this study were to investigate indications for thyroxine prescription in the United Kingdom and to examine the frequency of abnormal serum thyroid stimulating hormone concentrations in those prescribed thyroxine for hypothyroidism. This was in order to determine the relevance of measurement of thyroid stimulating hormone level in monitoring thyroxine therapy. Subjects receiving thyroxine were identified from the computerized prescribing records of four general practices in the West Midlands. Of 18,944 patients registered, 146 (0.8%) were being prescribed thyroxine; 134 of these had primary hypothyroidism and the remainder had other thyroid or pituitary diseases prior to treatment. Of the 97 patients with primary hypothyroidism who agreed to have their thyroid stimulating hormone level measured, abnormal serum levels were found in 48%, high levels in 27% and low levels in 21%. There was a significant relationship between prescribed thyroxine dose and median serum thyroid stimulating hormone level: high hormone levels were found in 47% of those prescribed less than 100 micrograms thyroxine per day, while low levels were found in 24% of those prescribed 100 micrograms or more. Thus, thyroxine prescription was common in the four practices sampled, although indications for its use were appropriate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Circulating lipids and minor abnormalities of thyroid function.

OBJECTIVE: We determined the effect of subclinical hyperthyroidism (defined as low circulating TSH with normal serum free T4) and subclinical hypothyroidism (raised serum TSH with normal free T4) on fasting levels of blood lipids. DESIGN: Prospective study of lipid concentrations in patients identified as having abnormal TSH. PATIENTS: Patients were identified in a population screening study of those over 60 years, with persistently low TSH with normal free T4 (n = 27) or high TSH but normal free T4 (n = 57). Patients were matched to controls with normal serum TSH by age, sex and body mass index. MEASUREMENTS: Serum TSH, free T4, free T3, total cholesterol, low density lipoprotein (LDL) cholesterol and high density lipoprotein (HDL) cholesterol. RESULTS: Serum free T4 measurements were significantly higher in those with subclinical hyperthyroidism than in their controls (P < 0.001) and lower in those with subclinical hypothyroidism than in matched controls (P < 0.001). Measurement of fasting lipids in patients and controls revealed a marked (12.2%) reduction in serum total cholesterol in subclinical hyperthyroidism (P < 0.01); no significant difference in fasting lipids between patients with subclinical hypothyroidism and controls was observed. CONCLUSIONS: Differences in free T4 between those with low or high TSH and controls with normal TSH suggest that abnormalities of TSH directly reflect thyroid hormone excess and deficiency. A reduction in cholesterol in those with subclinical hyperthyroidism suggests a direct influence of thyroid hormone excess on lipid metabolism in these patients.

Aged↗
PubMed1992

The problem of diagnostic variability in general practice.

STUDY OBJECTIVE: The aim was to examine the scale, source, and relevance of variation between general practices in respect of the rates with which patients consulted with illnesses falling in each of several diagnostic groups. DESIGN: This study involved a general practice morbidity survey conducted over two years, 1970-72. All patients who consulted their general practitioners were identified and the number of these who consulted with diagnoses attributable to each of the 18 main chapters of the International classification of diseases were counted. Patients who consulted for more than one diagnosis within a chapter were counted once only; those who consulted for one or more diagnoses in each of several chapters were counted once for each chapter. SETTING: This was a national survey involving general practitioners in England and Wales. SUBJECTS: The study involved 214,524 patients from 53 selected general practices (115 doctors) who were registered with their general practitioners for the whole of the year 1970-71 and for whom their morbidity data had been linked with their social data from the 1971 census. MEASUREMENTS AND MAIN RESULTS: Using the numbers of patients on the practice lists as denominators, practice patient consulting rates (PPCR) were calculated for each practice and for each ICD chapter. Variability in chapter PPCR was examined by calculating coefficients of variation and, after allowance for random variation, coefficients of residual variation. There were large interpractice (doctor) variations in all chapter rates. These variations were only marginally attributable to: chance; different age, sex and social class mixes of practice populations; geographical locations; and practice organisation. The rates were, however, consistent from one year to the next for any one practice. Approximately half of the interpractice (doctor) diagnostic variability was associated with overall patient consulting behaviour. When the effects of this behaviour were discounted, any major residual diagnostic variability was confined largely to ICD chapters I-V, XVI, and XVII, ie, those chapters where aetiology forms the basis of classification. CONCLUSION: Variations in recorded diagnostic rates are mainly due to the consistent but idiosyncratic and selective exclusion by practitioners of some components from the total set which often coexist in a new diagnosis. Because of the scale of interpractice diagnostic variability, the use of algorithms and information technology is largely precluded from outcome studies, auditing procedures, and studies of practice work loads in general. However, (1) the consistency of any individual doctor's pattern of diagnostic recording from one year to another permits studies of trends; and (2) given a reasonable number of recording practices, the population mean practice consulting rates can be estimated with sufficient accuracy for many epidemiological research and administrative uses.

Age Factors↗
PubMed1991

Prevalence and follow-up of abnormal thyrotrophin (TSH) concentrations in the elderly in the United Kingdom.

Increasing use of assays for TSH with improved sensitivity as a first-line test of thyroid function has raised questions regarding prevalence and clinical significance of abnormal results, especially values below normal. We have assessed the thyroid status of 1210 patients aged over 60 registered with a single general practice by measurement of serum TSH using a sensitive assay. High TSH values were more common in females (11.6%) than males (2.9%). TSH values below normal were present in 6.3% of females and 5.5% of males, with values below the limit of detection of the assay present in 1.5% of females and 1.4% of males. Anti-thyroid antibodies were found in 60% of those with high TSH but only 5.6% of those with subnormal TSH. Eighteen patients were hypothyroid (high TSH, low free thyroxine) and one thyrotoxic (low TSH, raised free thyroxine) at initial testing. Seventy-three patients with elevated TSH but normal free T4 were followed for 12 months; 13 (17.8%) developed low free T4 levels and commenced thyroxine, TSH returned to normal in four (5.5%) and 56 (76.7%) continued to have high TSH values. Sixty-six patients with TSH results below normal were followed. Of the 50 subjects with low but detectable TSH at initial testing, 38 (76%) returned to normal at 12 months; of those 16 with undetectable TSH followed, 14 (87.5%) remained low at 12 months. Only one subject (who had an undetectable TSH) developed thyrotoxicosis. In view of the marked prevalence of thyroid dysfunction in the elderly, we suggest that screening of all patients over 60 should be considered.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Disease concurrence in diabetes mellitus: a study of concurrent morbidity over 12 months using diabetes mellitus as an example.

STUDY OBJECTIVE: The aim was to examine disease concurrence, using diabetes mellitus as an ullustrative example. DESIGN: The study involved a general practice morbidity survey, conducted over 12 months in 1981-82. All patients who consulted their general practitioners with a diagnosis of diabetes mellitus (type 1 or type 2) were identified and the number of these who consulted with additional morbidities were counted for each rubric of the Royal College of General Practitioners' modification of the International Classification of Disease. These observed numbers were then compared with expected numbers calculated from the total non-diabetic population after standardisation by age. Standardised person consulting ratios (SPCR) were derived and the 99% confidence intervals (CI) surrounding these values calculated. SETTING: This was a national survey involving the whole of England and Wales. PATIENTS: The study involved 280,000 patients from selected general practices, of whom 953 males and 1035 females consulted their general practitioners with diabetes. MEASUREMENTS AND MAIN RESULTS: In an examination of 80 disease rubrics in the diabetic population in which there were at least 20 observed or expected cases, there were 34 among males and 28 among females in which there were increased values of the SPCR, and none in which the SPCR was decreased. SPCRs were high for infections generally (bacterial, fungal, and viral) and particularly so for cardiovascular disorders and for hypothyroidism in males. Though SPCRs for upper respiratory infections were increased, those for asthma and hay fever were not. SPCRs for neoplasms as a group were not raised. CONCLUSION: By confirming other work and widely held clinical opinion, this study has shown the potential of this data base for the examination of disease concurrence.

Cohort Studies↗