The influence of population characteristics on variation in general practice based morbidity estimations.

BACKGROUND: General practice based registration networks (GPRNs) provide information on morbidity rates in the population. Morbidity rate estimates from different GPRNs, however, reveal considerable, unexplained differences. We studied the range and variation in morbidity estimates, as well as the extent to which the differences in morbidity rates between general practices and networks change if socio-demographic characteristics of the listed patient populations are taken into account. METHODS: The variation in incidence and prevalence rates of thirteen diseases among six Dutch GPRNs and the influence of age, gender, socio economic status (SES), urbanization level, and ethnicity are analyzed using multilevel logistic regression analysis. Results are expressed in median odds ratios (MOR). RESULTS: We observed large differences in morbidity rate estimates both on the level of general practices as on the level of networks. The differences in SES, urbanization level and ethnicity distribution among the networks' practice populations are substantial. The variation in morbidity rate estimates among networks did not decrease after adjusting for these socio-demographic characteristics. CONCLUSION: Socio-demographic characteristics of populations do not explain the differences in morbidity estimations among GPRNs.

Data quality improvement in general practice.

BACKGROUND: The importance of routine data generated by GPs has grown extensively in the last decade. These data have found many applications other than patient care. More attention has therefore been given to the issue of data quality. Several systematic reviews have detected ample space for improvement of data quality. A new review was conducted in order to find out which methods of improvement are effective. METHOD: The Medline database was searched using an iteratively composed set of terms and MeSH (Medical Subject Headings) headings. Only papers that focused on explicit attempts at improving data quality of medical records in general practice were included. RESULTS: Twelve studies met the inclusion criteria. No study used patient-based comparison of records with external sources as the method to assess data quality improvement. Ten studies used internal indicators or markers of data quality instead. Attempts at data quality improvement often involve some sort of individualized feedback, and nearly all attempts seem to have some positive effect. Only one of the included studies fulfilled the basic methodological requirements of an intervention study. The most recent studies used a simple before-after design. CONCLUSION: No intervention to improve data quality has been put to a rigorous enough test. We still lack empirical knowledge as to how improvement can be brought about.

The patient as a source to improve the medical record.

BACKGROUND: The problem list is an important tool in general practice for care as well as research purposes. As the central part of the problem-oriented medical record, it lists the main medical problems which the GP wants to have knowledge of during any patient encounter. The assessment of its quality is usually made by comparing with other sources of information on the patient's problems. OBJECTIVE: This study addresses the question of to what extent the problem list can be improved by asking the patient about their own medical problems. METHODS: During 7 weeks, all patients who visited three GPs in a health care centre in an Amsterdam suburb were interviewed. During the interview, they were confronted with the problem list made by their own GP and stimulated to make suggestions for addition or removal of problems. RESULTS: All in all, patients were in agreement with 88% of all listed problems. The completeness of the problem list could be increased by 28%, while 4% ultimately were removed: a net gain of 24%. CONCLUSION: The patient can be used as a sourcetool for improvement of the quality of the problem list when its prime function is patient care. It becomes more complicated when the problem list also serves a research purpose. Clear inclusion rules will then have to be formulated.

[Moroccans' opinions about general practitioners: analyzing reasons for consultation]. / Marokkanen bij de huisarts aan het woord; de mate waarin de huisarts de reden van komst achterhaalt.

OBJECTIVE: To determine whether there is a difference in the extent to which the GP succeeds in establishing the reasons for consultation of Moroccans and those of the Dutch; and whether the opinion of Moroccans about the GP's consultation differs from that of the Dutch. DESIGN: Analysis of patient interviews and GP's consultations. METHOD: In 11 general practices in Amsterdam and The Hague in May 1997, 50 Moroccan adults and 50 Dutch individuals were asked for their reasons to attend before the consultation and in the mother language; a distinction was made between the actual complaint and the expectations with regard to the consultation. The GPs recorded these data after every consultation. The complaints were coded by organ system and by nature of complaint, following which agreement of the assessments was scored on a scale ranging from 0 to 100. RESULTS: Both groups comprised 20 men and 30 women. The mean age of the Moroccans was 38.6 years (SD: 13.8), that of the Dutch 56.4 years (SD: 16.7). The GPs established complaints of Moroccan patients not as well as those of Dutch patients (score: 73.9 versus 87.3); the difference was more pronounced where patients with only elementary education were concerned (67.0 as against 86.1). The GPs were able to establish the expectations with regard to the consultation nearly as often for the Moroccan as for the Dutch patients (58.5 versus 55.9). Moreover, the Moroccans were as positive about the course of the consultation as the Dutch. Except for communication problems among the lower educated, none of the problems indicated appeared to be experienced more often by the Moroccans than by the Dutch. CONCLUSION: A large part of the complaints presented by lower educated Moroccan patients were interpreted differently by the GP. For Moroccans with a higher education, the care was comparable with that among the Dutch.

Prevalence of depression in patients with chronic obstructive pulmonary disease: a systematic review.

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) have repeatedly been characterised as a population of chronically ill patients with a higher than normal prevalence of depression. Susceptibility for depression has been noted in patients with certain other chronic conditions. This systematic review was conducted to achieve a more definite answer to the question: do patients with COPD show a higher than normal prevalence of depression? METHODS: Studies in English language journals were retrieved by an electronic search over the period from 1966 to December 1997 and by an extended search of reference lists, and were included or excluded according to a system of diagnostic and methodological criteria. RESULTS: Ten studies were included, of which only four had a case-control design. Three of the case-control studies reported an increased prevalence of depression among patients with COPD which was statistically significant in only one. The fourth controlled study found a significantly increased depression score among COPD patients. Of the remaining six uncontrolled studies three found a high baseline prevalence of depression among their study group. CONCLUSIONS: An association between COPD and depression was found in the four controlled studies. The two methodologically best conducted studies that did not detect a statistically significant higher prevalence lacked power. The two studies that did find a significant association used a questionable depression measure. The prevalence of depression was high compared with general population figures in three of six non-controlled studies. The empirical evidence for a significant risk of depression in patients with COPD remains inconclusive, due to the poor methodological quality of most of the published studies, the lack of studies with an adequate sample size, and variability in instruments and cut off scores used to measure depression.

The accuracy of creatinine methods based on the Jaffé reaction: a questionable matter.

The determination of creatinine in serum based on the Jaffé reaction was evaluated with four current analysers. In particular, the comparability of results was determined also with survey specimens. Recalibration of 3 out of 4 modifications was necessary, based on the results of patient samples as verified with a HPLC-method. One of the methods proved to give an unacceptable scatter for the results in the lower range (30-150 mumol/l). A limited interference study (haemoglobin, lipids, bilirubin and acetone) and a method assessment with quality control sera supported the conclusion that the overall accuracy of creatinine methods based on the Jaffé reaction is questionable.

Improvements in creatinine methodology: a critical assessment.

A large evaluation study, analytical as well as clinical, was performed on four published improvements for the determination of creatinine in serum. Two of the methods were based on the Jaffé reaction, the other two were enzymatic methods. Analytically, all four methods showed a similar performance. In the analysis of numerous specimens from advanced care departments, however, the methods performed differently. The two enzymatic procedures scored better than the two Jaffé methods, when compared with an HPLC-based reference method. However, even the best methods produced outliers and a larger scatter than that obtained with "normal" specimens.

Serum iron and proficiency testing: a dilemma.

We present and discuss observations regarding the results of the serum iron determination as seen in various surveys. The reference method proved to score different in our hands judging on the performance in the Dutch and German quality assessment schemes. Furthermore, it is clear and frustrating that these scores, representing the most accurate results, are becoming more and more labeled "out of acceptable range".

Use of symptoms and signs to diagnose maxillary sinusitis in general practice: comparison with ultrasonography.

OBJECTIVE: To establish the incidence of maxillary sinusitis in general practice and the predictive value of symptoms and signs. DESIGN: Population based study. SETTING: 9 general practices with 15,220 patients aged 15 years and older on the list. PATIENTS: 400 patients with 441 episodes in whom practitioners intended to confirm or to exclude sinusitis. MAIN OUTCOME MEASURES: Results of ultrasonography and signs and symptoms associated with positive results. RESULTS: 212 of the 441 episodes were confirmed by ultrasonography. 15.7 episodes occurred per 1000 adults per year. The five symptoms beginning with common cold (beta coefficient = 1.035), purulent rhinorrhoea (0.996), pain at bending (0.950), unilateral maxillary pain (0.640), and pain in teeth (0.606) were associated with positive results on ultrasonography. General practitioners' clinical diagnoses were correct in 177 episodes, false positive in 88, false negative in 22, and uncertain in 154. With an algorithm using the five weighted symptoms 243 of the diagnoses would have been correct, but 110 would remain uncertain and 44 cases would have been missed. CONCLUSION: The five symptoms algorithm would improve diagnostic accuracy of general practitioners, but incorrect and uncertain diagnoses cannot be avoided.

General practice in St. Eustatius: II. Results - abstract

During the 1-year period, September 1, 1987 to August 31, 1988, the only 2 general practioners (GP) on the island of St. Eustatius recorded patient-based and episode-oriented data concerning 7,222 encounters with patients. The average population was 1,996 persons and the average encounter rate was 3.6 per person. The lower the social class of the patient the higher was the average encounter rate. Thirty-five per cent of the population was not seen at all. The special clinics for children, pregnant women and prostitutes, district calls and the 18-bed hospital accounted for 22 per cent, and the open morning clinic, 66 per cent of all encounters. Patients frequently visited the GP after hours (11 per cent). The most frequent patient-initiated reasons for encounter were of 2 kinds; requests for bloodpressure check (5 per cent), for contraception (3 per cent), for complaints such as cough (4 per cent), headache (3 per cent), fever, abdominal pain, injuries and tiredness (2 per cent each). "No disease" was an important diagnostic rubric (5 per cent). Other frequently occurring episodes were upper respiratory tract infection, influenza, other viral diseases and acute bronchitis (3 per cent each). Chronic diseases occurring frequently were uncomplicated hypertension (2 per cent, prevalence, 60/1,000 persons) and diabetes (1 per cent, prevalence, 36/1,000 persons). An average of 3.2 interventions per encounter was recorded, mainly partial examination (36 per cent), medication (25 per cent) and advice (23 per cent). In 3 per cent of encounters, a patient was referred to a specialist. Patient-based and episode-based morbidity recording provide useful data that describes the content of general practice on a small Caribbean island (AU)

General practice in St. Eustatius: I. Tools and methods - abstract

The Transition Project comprises a network of 25 family practioners (FP), including two on the island of St. Eustatius, the Netherland Antilles. These doctors register all encounters with all patients during at least one year. The aim of the Project is to construct an episode-oriented epidemiology of family practice. During each encounter, the patient's reasons for the encounter, the FP's diagnostic interpretation and the diagnostic and therapeutic interventions are recorded. Classification and coding are done by the FPs themselves, using the International Classification of Primary Care (ICPC) which is a two-axial classification system specially designed for use in primary care medicine. Problem-oriented encounter forms were used, copies of which were sent to Amsterdam for data entry. In the period September 1, 1987 to August 31, 1988, the 2 FPs recorded 7,222 encounters. Two sources of error, by the coding FP and during the data entry process were assessed. In a random sample of 3 per cent of encounters, the data stored in the computer were compared with the coded information and the hand written notations of the FP on the original form. It was estimated that 4.3 per cent of all episodes had an incorrect title, mainly due to coding errors made by the FP, and 4 of every 100 episodes were missing, most of which were lost during transport of forms. It was concluded that the data collected were valid and had minimal methodological sources of error (AU)

Determination of phenoxyacid herbicides in water. Polymeric pre-column preconcentration and tetrabutyl-ammonium ion-pair separation on a PRP-1 column.

Optimum conditions for preconcentration of phenoxyacid herbicides from water on polymeric material and separation on an analytical column (PLRP-S) and PRP-1 respectively) have been achieved. The method consists of (a) an on-line preconcentration at pH 3, (b) clean-up with four (precolumn) bed volumes of acetonitrile-water (30:70) at pH 3 and (c) isocratic analytical separation at pH 11 with 0.01 mol/l tetrabutylammonium as the ion-pair reagent and acetonitrile-water (30:70) as the eluent. Data on the repeatability of the method, sample flow dependence and sorption capacity are reported. For reliable integration of the chromatogram a clean-up step was introduced. This washing procedure however is more effective for tap-water than for surface water samples. The results of the method are promising and indicate that 10-50 ml of surface water can be applied to the precolumn without breakthrough. Detection limits in surface water samples are 0.1-0.5 micrograms/l whereas those in tap water are 10-50 ng/l. The applicability fo the method was tested. The results of this method were in good agreement with gas chromatographic-mass spectrometric results, and only ca. 0.1 microgram/l lower over the entire range, whereas the analysis time was much shorter. The potential of this technique for automation was demonstrated using a microprocessor-controlled column-switching unit, resulting in a reduction of the total analysis time to ca. 20 min.

Surveys of neonatal bilirubin. An evaluation.

Experience in surveying the neonatal bilirubin determination in the Netherlands is described. Initially it was organized as a local activity (the Rotterdam area), then later enlarged to a national scale (some 150 participants). A number of items is discussed i.e. the initial improvements, which stabilized at an interlaboratory imprecision of about 8%, and further changes that could improve this rather high imprecision.

The influence of the label on the quality of a solid-phase immunoassay: evaluation of a commercial ELISA kit for serum ferritin.

A new Enzyme Linked Immuno Sorbent Assay (ELISA) kit for the determination of serum ferritin has been compared with another ferritin kit based on the Immuno Radio-Metric Assay (IRMA) approach, both assays containing similar antibodies. Based on these studies, we found the within-run precision of the ELISA (and IRMA) to have coefficients of variation of 4-10% and 2-6% respectively, over a concentration range of 12-600 micrograms/l. The between-run precision for the same concentration range exhibited a CV range of 9-13% and 7-11% respectively. The sensitivities were found to be 1.4 micrograms/l and 0.9 microgram/l. The mean recovery was 103% for the ELISA procedure. It was found that, using the serum dilution technique, the linearity reached to 1000 micrograms/l. In the ELISA procedure no influence from the so-called "high dose hook effect" was observed. While EDTA-plasma produced 6% lower values than serum in the ELISA technique, no interference from albumin, gamma-globulins and mild haemolysis was observed. Stability problems with the ELISA kit were not encountered. A comparative analysis of multiple specimens demonstrated nearly identical values with r = 0.994 and y = 0.87 x1.01. The quality and ease of operation of the ELISA approach compared with other techniques are discussed. In conclusion it is possible to replace a radio-label in an immunoassay with an enzyme-label with the same degree of reliability and other parameters of quality control exhibited by radioimmunoassays.

The determination of total bilirubin with the Du Pont ACA with respect to neonatal sera.

The interference of hemoglobin in the determination of total bilirubin with the Du Pont ACA was studied. The method seemed of limited value in our opinion especially with respect to neonatal sera. By changing the wave-length setting a rather broad plateau was found when the hemoglobin concentration was plotted against the actual bilirubin concentration. On the basis of these findings a new calibration graph was constructed and programmed into the ACA. The new method correlates well with two other micro bilirubin techniques.

A simple automated method for the fluorometric titration of calcium in biological fluids,.

A new automatic device has been developed for the determination of the calcium content in biological fluids. The method is based on a fluorometric titration technique, in which calcium is titrated with ethyleneglycolbis-(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA). The end-point of the titration is indicated by quenching of the fluorescence of a calcium-calcein complex, in which calcein is the fluorescein-complexone indicator. To obtain proper results we found it necessary to use a 1 molar potassium hydroxide solution as titration medium. The results are printed out directly in concentration units (mmol/l). In order to carry out these determinations, several electronic and mechanical devices, including a sample-changer, titration cabinet with built-in fluorometer, control unit and electron titrator, were developed. Together they form the new calcium automatic device of which several qualitites such as precision, recovery and correlation have been studied. The disturbing influence of bilirubin has been minimized by using an excitation wavelength of 492 nm, at which there is nearly no absorption by bilirubin. At a concentration of bilirubin of as much as 500 micronmol/l, the recovery of calcium is still about 96%.