Practical guide to the diagnostics of ruminant gastrointestinal nematodes, liver fluke and lungworm infection: interpretation and usability of results

The diagnostics of ruminant parasites remains one of the cornerstones for parasite control best practices. Field veterinarians have several techniques at their disposal (fecal egg count, coproculture, FAMACHA®, plasma pepsinogen, ELISA-Ostertagia, ELISA-Fasciola, Baermann and ELISA-Lungworm) for the identification and/or quantification of gastrointestinal nematodes, lungworms and liver fluke infecting small ruminants and cattle. Each of these diagnostic tools has its own strengths and weaknesses and is more appropriate for a specific production operation and/or age of the animal (young and adults). This review focuses on the usability and interpretation of the results of these diagnostic tools. The most advanced technical information on sampling, storage, advantages and limitations of each tool for different types of production operations and animal categories is provided.

Physician deaths from COVID-19 have been lower than expected

Background

More than 100 US physicians have died from COVID-19. I considered the number of US physician deaths in comparison to the expected COVID death rate in the general population.

Aims

To estimate the whether US physicians are at increased risk of death from COVID-19 due to occupational exposures.

Methods

COVID-related physician deaths were identified through searches using Medscape In Memoriam, and multiple internet searches using Google and Facebook. An obituary or death notice was obtained in all but one case. Death rates among physicians were compared to the expected rate based on COVID deaths in the US population.

Results

Up to 7 October 2020, there were 108 deaths among US physicians. Physicians make up about 0.33% of the US population. By 1 October 2020, there were 210 000 COVID deaths in the US population with 693 expected physician deaths. Observed deaths were 16% of expected. Seventy-five per cent of the deaths occurred among physicians older than age 60 and about half appeared to be among those retired from clinical practice.

Conclusions

Observed physician deaths were significantly below expected based on deaths the general population. Prudent use of personal protective equipment may explain the lower-than-expected death rates.

Importation of macrocyclic lactone resistant cyathostomins on a US thoroughbred farm

Anthelmintic resistance in equine cyathostomins is both widespread and highly prevalent in the benzimidazole and tetrahydropyrimidine classes; however, reports of resistance to macrocyclic lactone (ML) drugs are sparse and sporadic. This study reports a case of clear ML resistance in a group of Thoroughbred yearlings imported from Ireland to the US in 2019. Fecal egg count reduction (FECR) following ivermectin administered in February 2020 demonstrated 100% reduction in the US bred yearlings, but 93.5%, 70.5%, and 74.5% reduction in three groups of the imported yearlings. The two former groups were then retreated with ivermectin, yielding FECRs of 33.8% and 23.5%, respectively. Horses from these two groups were then assigned randomly to two possible treatments; moxidectin or a triple combination of moxidectin, oxibendazole, and pyrantel pamoate. The groups treated with moxidectin had FECRs of 90.2%, 57.3%, and 50.0%, while the triple combination had a 100% FECR in all treated groups. Subsequently, the efficacy of ivermectin was reassessed in June 2020 yielding FECRs of 99.8%, 87.7%, and 62.0% in the three imported groups. The FECRs of the US bred yearlings all remained in the 99–100% range. This is the first study to clearly demonstrate ML resistance in cyathostomins and to confirm the suspicion through reassessment. These data demonstrate that ML-resistant cyathostomins were imported from Ireland and serve to illustrate that the global movement of horses has the potential to quickly spread ML-resistant parasite isolates around the world. The equine industry is strongly encouraged to routinely monitor anthelmintic efficacy, so occurrence of ML resistant cyathostomins can be detected and appropriate interventions implemented as early as possible.

•

Reduced macrocyclic lactone efficacy in yearlings imported from Ireland.

•

Ivermectin efficacy was retested twice and was reduced on all occasions.

•

100% strongyle fecal egg count reduction in US bred yearlings on all occasions.

•

A combination of moxidectin, oxibendazole and pyrantel pamoate was 100% effective.

•

Global movement of horses likely to spread macrocyclic lactone resistance quickly.

Equine parasite control and the role of national legislation - A multinational questionnaire survey

Experts recommend a change in the control of equine parasites across the world in order to adopt a surveillance-based approach utilizing parasite faecal egg counts (FEC). Several European countries have implemented prescription-only restrictions of anthelmintic usage by law, which is in stark contrast to US, where all anthelmintic products continue to be available over the counter. This study aimed to describe and compare equine parasite control strategies employed in Germany, Austria, the Netherlands, US, and Denmark. An invitation to participate in an online questionnaire survey was published on a large equine news website in each of the participating countries. The main focus of the study was on usage of FEC and anthelmintic treatment intensity in three different equine age groups; foals, 1-3 year-olds and >3 years old. A total of 3092 respondents participated in the study. Danish respondents used significantly more faecal analyses in their parasite control strategies than participants from the other four countries (p < 0.0001). Similarly, Danish participants administered significantly fewer anthelmintic treatments per horse per year (p < 0.0001) independent of the age of the horse, and had been using a selective treatment strategy for a significantly longer time period than their counterparts in other countries (p < 0.0001). Only minor differences were found between respondents from the other four countries. This is remarkable as both Austria and Germany have had prescription-only restrictions for 3-4 decades. Yet, their parasite control strategies were more similar to those employed by American respondents. The Netherlands had only recently introduced prescription-only restrictions by the time this survey was conducted which can explain why Dutch respondents were also similar to their American counterparts. Taken together, this study illustrates substantially different worm control strategies practiced in Denmark, and this difference cannot be explained by legislation alone.

The impact of social support in pulmonary rehabilitation of patients with chronic obstructive pulmonary disease

Social support has been shown to be an important mediator of health status and survival in chronic illness but little information is available in patients with lung diseases. We used the Social Support Questionnaire (SSQ) to examine the relationships of number of persons (SSQ-N) and satisfaction (SSQ-S) with other measures of health status, treatment changes, and survival in 110 patients with chronic obstructive pulmonary disease (COPD) participating in a randomized, controlled clinical trial of pulmonary rehabilitation (PR). Included in the analyses were measures of lung function (FEV1.0), exercise tolerance (maximum and endurance), symptoms ratings, age, self-efficacy, depression, and gender. At baseline, SSQ-N and SSQ-S were correlated positively with self-efficacy and negatively with depression and self-reported shortness of breath (SOB). SSQ-N was also correlated with disease severity and maximum exercise tolerance (FEV1.0 and VO2 max). Using the Cox Proportional Hazard Model, SSQ-S was significantly related to improved survival up to six years. However, in multivariate analysis, after adjusting for FEV1.0 and SOB which were better predictors of survival, SSQ-S was marginally significant. SSQ-S and survival were computed separately for males and females across treatment groups. SSQ-S was significantly related to mortality for women but not for men. We conclude that social support is related to measures of physical and psychological function in patients with COPD and may influence improvement and survival after pulmonary rehabilitation.

Evaluation of the validity of the Quality of Well-being Scale in Trinidad and Tobago

Both developing countries in the Caribbean and developed countries face resource allocation challenges. However, cost-effectiveness analysis instruments that may assist in allocation of resources have not been tested in Caribbean countries. Trinidad and Tobago is an advantageous location to test an instrument for potential use in the Caribbean. It has a single payer healthcare system and a literate population. Due to historical and current migration from other Caribbean countries, the population might be a fair representation of English-speaking Caribbean nations. We tested the validity of the Quality of Well-being Scale (QWB) on a sample of the non-institutionalized general population in Trinidad. The survey included reports of chronic conditions and items from the Trinidad and Tobago National Health Interview Survey. Data were analyzed using a multivariable regression model. One adult from each of 235 households consented to the interview. The results are consistent with results obtained in the United States of America. Being older female, more chronic conditions and more symptoms/problems were significantly associated with lower mean QWB scores. These results suggest that the QWB with US-derived weights show evidence of validity in Trinidad and Tobago. Thus, health decision makers can use the QWB to compare the effects of different health conditions and health interventions. In addition, investigators can make cross-cultural comparisons of QWB scores for diseases or health conditions.

Statistical approach to measure the efficacy of anthelmintic treatment on horse farms

Resistance to anthelmintics in gastrointestinal nematodes of livestock is a serious problem and appropriate methods are required to identify and quantify resistance. However, quantification and assessment of resistance depend on an accurate measure of treatment efficacy, and current methodologies fail to properly address the issue. The fecal egg count reduction test (FECRT) is the practical gold standard for measuring anthelmintic efficacy on farms, but these types of data are fraught with high variability that greatly impacts the accuracy of inference on efficacy. This paper develops a statistical model to measure, assess, and evaluate the efficacy of the anthelmintic treatment on horse farms as determined by FECRT. Novel robust bootstrap methods are developed to analyse the data and are compared to other suggested methods in the literature in terms of Type I error and power. The results demonstrate that the bootstrap methods have an optimal Type I error rate and high power to detect differences between the presumed and true efficacy without the need to know the true distribution of pre-treatment egg counts. Finally, data from multiple farms are studied and statistical models developed that take into account between-farm variability. Our analysis establishes that if inter-farm variability is not taken into account, misleading conclusions about resistance can be made.

Accuracy of the FAMACHA system for on-farm use by sheep and goat producers in the southeastern United States

FAMACHA is a practical on-farm system designed to provide small ruminant producers a tool for improving their management of Haemonchus contortus infections. Although this system has become very popular and widely accepted by small ruminant producers in many regions of the southern United States, there is very limited data reported on the effectiveness of the FAMACHA system when performed by farmers. The objective of this study was to evaluate the accuracy of the FAMACHA system for on-farm use by small ruminant producers during the summer season. Small ruminant producers from Georgia, Louisiana, Florida, and Puerto Rico were trained to use the FAMACHA system by veterinarians and scientists experienced with this method. FAMACHA scores were assigned at least every 2 weeks by producers to weaned and mature sheep (n=552) and goats (n=676) of various breeds and ages between April and September 2004. At intervals that varied among farms from 2 to 8 weeks, researchers determined body condition scores (BCS; 1=thin and 5=fat) and collected blood and feces from a group of animals selected randomly to determine packed cell volume (PCV) and fecal egg counts (FEC). Two separate anemia thresholds were evaluated; these were defined by either FAMACHA score (>or=3 versus >or=4) or PCV (<or=19 versus <or=15%). The correlation between FAMACHA scores and PCV or FEC was high for both sheep and goats (P<0.001). Specificity was maximized when FAMACHA scores of 4 and 5 were considered anemic, but sensitivity was low. Sensitivity for detecting anemic animals was 50% for sheep and 89% for goats when eye score values of >or=3 were considered anemic and PCV cutoff was <or=15%. The percentage of false negatives (anemic animals not identified by FAMACHA evaluation) was less than 5% in sheep and less than 1% in goats when FAMACHA scores>or=3 were considered anemic and PCV cutoff was <or=15%. In both sheep and goats, predictive value of a negative was greater than 90% for all anemia and eye score categories. These data indicate that the FAMACHA method used by producers is a valuable tool for identifying anemic sheep and goats in the southern United States and Puerto Rico.

A novel approach for combining the use of in vitro and in vivo data to measure and detect emerging moxidectin resistance in gastrointestinal nematodes of goats

Ivermectin and moxidectin are closely related avermectin/milbemycin anthelmintics and available data suggest that side resistance occurs with these two drugs. However, moxidectin remains effective against many species of ivermectin-resistant worms due to its higher potency. The larval development assay (LDA) is routinely used to diagnose ivermectin resistance in Haemonchus contortus but laboratory diagnosis of moxidectin resistance is hampered by the lack of any validated in vitro tests. The objective of this study was to measure the relative susceptibility/resistance of H. contortus to moxidectin on goat farms in Georgia, and to validate the DrenchRite LDA for detecting resistance to moxidectin. Fecal egg count reduction tests (FECRT) were performed at five different moxidectin dose levels and DrenchRite LDAs were performed in duplicate on nine meat goat farms in Georgia, USA. To improve our ability to make inferences on the relative levels of resistance between farms, FECRT data were first analysed using a linear mixed model, and then Tukey's sequential trend test was used to evaluate the trend in response across dose levels. LDA data were analysed using log-dose logit-response and probit models. Using these statistical results, we were able to rank the nine farms from the least to the most resistant, and to develop a set of criteria for interpreting DrenchRite LDA results so that this assay can be used to diagnose both clinically apparent moxidectin resistance, as well as sub-clinical emerging resistance. These results suggest that our novel approach for examining these types of data provides a method for obtaining an increased amount of information, thus permitting a more sensitive detection of resistance. Based on results of the LDA, moxidectin-resistant farms had resistance ratios, compared with an ivermectin-sensitive farm, ranging from 32 to 128, and had resistance ratios of 6-24 compared with an ivermectin-resistant/moxidectin naive farm. Moxidectin resistance was diagnosed both in Haemonchus and Trichostrongylus on almost half of the farms tested, despite this drug only being used on these farms for 2-3 years.

Development and characterization of microsatellite markers for the canine hookworm, Ancylostoma caninum

Microsatellites are repetitive genomic elements that show high levels of variation and therefore provide excellent tools to study the genetics of eukaryotic organisms. Hookworms are extremely common and important nematode parasites of humans and animals, causing potentially serious disease morbidity. Control of hookworms in dogs is achieved by frequent treatment with anthelmintics, and in humans, anthelmintics are frequently administered in a mass-treatment community-wide approach. Understanding the population genetics of hookworms has important implications for studies on the development and spread of drug resistance. We investigated the genome of Ancylostoma caninum for microsatellites by developing and then screening an enriched genomic library as well as by data mining published sequences of a whole genome shotgun library. Investigations revealed a high abundance of trinucleotide repeats. Dinucleotide repeats were characterized by a high number of AT, GA, and GT repeats. After testing and optimization of 68 markers, a panel of 34 polymorphic microsatellite markers were selected. Microsatellite analysis of hookworm isolates revealed a high degree of polymorphism, which was not influenced by the length of the repeats. This panel of microsatellite markers makes it possible to pursue investigations on the population genetics of A. caninum. Furthermore, a number of the markers demonstrated suitability for analysis of the human hookworm species Necator americanus and A. duodenale.

Targeted selective treatment for worm management—How do we sell rational programs to farmers?

Seriously escalating global anthelmintic resistance in gastrointestinal nematodes of small ruminants has spawned a variety of alternatives to anthelmintics for worm management, based on the need for sustainable Integrated Parasite Management (sIPM). Pivotal to the sIPM approach is the concept of refugia, the proportion of a given parasite population that escapes exposure to control measures. By balancing drug applications with the maintenance of refugia, the accumulation of anthelmintic resistance alleles in worm populations can be considerably delayed, while still providing good levels of control. The over-dispersed nature of parasitic infections provides an opportunity to achieve this balance, by targeting treatments to the members of a flock or herd that are least tolerant to nematode infection. However, implementation of this strategy has only recently become feasible, with the development of the FAMACHA((c)) system for clinical evaluation of anaemia due to haemonchosis. Subsequently, the use of milk yields has proven an effective indicator in dairy goats infected predominantly with nematodes other than Haemonchus contortus. In addition, short-term weight changes and perhaps also body condition scoring may provide indices of parasitism, permitting the rapid identification of animals likely to benefit from treatment. However, sIPM and refugia-based approaches are more complex than whole-flock treatments in conventional programs, and adoption by farmers is most likely where the theoretical basis is understood. As close communication with informed advisors is generally limited, there is a danger that sIPM will remain a theoretical concept without alternative modes of communication. The development of computer-based decision support programs, which use epidemiological, seasonal and clinical information to provide recommendations for specific situations, should be accorded high priority in the future development of worm management systems.

Sericea lespedeza hay as a natural deworming agent against gastrointestinal nematode infection in goats

Infection with gastrointestinal nematodes (GIN), particularly Haemonchus contortus, is the biggest constraint to profitable goat production in the United States (US). Due to widespread prevalence of anthelmintic resistance in goat GIN, alternative, non-chemical control methodologies are needed to increase profitability of small ruminant industries. A study was designed to test the efficacy of a high condensed tannin (CT) legume, sericea lespedeza [SL, Lespedeza cuneata (Dum.-Cours. G. Don)] against GIN of goats fed in confinement. The goats were given a trickle infection of 500 H. contortus larvae/animal three times per week during the trial to simulate natural infection. Twenty Boer bucks (6-8 months old) were fed bermudagrass [BG, Cynodon dactylon (L.) Pers.] hay plus concentrate for 5 weeks in confinement and then 10 animals were switched to SL hay for an additional 7 weeks. Throughout the trial, feces and blood were collected weekly from individual animals to determine fecal egg count (FEC) and blood packed cell volume (PCV). Fecal cultures were made weekly from pooled samples to determine treatment effects on GIN larval development. All goats were slaughtered at the end of the trial, with adult worms in the abomasum and small intestine of each goat recovered, counted, and identified to species. Feeding SL hay to goats significantly (P<0.01) reduced FEC and increased PCV compared with BG hay. In addition, a lower percentage of ova in feces from SL-fed goats developed into infective (L3) larvae. There was a direct effect of SL hay on adult worms, with significantly (P<0.01) lower numbers of both abomasal (H. contortus, Teladorsagia circumcincta) and small intestinal (Trichostrongylus colubriformis) nematodes compared with goats fed BG hay. Feeding SL hay to goats is an effective means of controlling parasitic nematodes and may be a potential supplement/replacement for chemical anthelmintics.

Reliability and validity of dyspnea measures in patients with obstructive lung disease

Dyspnea, the clinical term for shortness of breath, is the primary symptom and an important outcome measure in evaluations of patients with lung disease. It is a subjective symptom that has proved difficult to quantify. Many dyspnea measures are available, yet it is difficult, based on the existing literature, to determine the most reliable and valid. In this study, we evaluated 6 measures of dyspnea for reliability and validity: (a) Baseline Dyspnea Index (BDI) and Transition Dyspnea Index, (b) UCSD Shortness of Breath Questionnaire (SOBQ),(c) American Thoracic Society Dyspnea Scale, (d) Oxygen Cost Diagram, (e) Visual Analog Scale, and (f) Borg Scale. Subjects were 143 patients (74 women) and 69 men) with obstructive lung disease, ages 40 to 86, FEV(1.0) 0.36 to 3.53 L, FVC 1.07 to 5.74 L. Dyspnea measures were assessed for test-retest reliability internal consistency, interrater reliability, and construct validity (i.e., correlations among dyspnea measures and correlations of dyspnea measures with exercise tolerance, health-related quality of life, lung function, anxiety, and depression). Results suggest that the SOBQ and BDI demonstrated the highest levels of reliability and validity among the dyspnea measures examined.

Estimating the risk of long-term erectile, urinary and bowel symptoms resulting from prostate cancer treatment

Reports on long-term complications resulting from treatment for localized prostate cancer are very inconsistent. In order to estimate the risks of long-term erectile dysfunction, urine symptoms and bowel symptoms following prostatectomy (RP), external conventional or conformal beam radiation (ERT or CRT) and brachytherapy (BRT), 98 papers from the PubMed and Cochrane Clinical Trial databases were selected, reviewed and critically evaluated. The majority of papers were institution-based retrospective and prospective follow-up studies; only two of these studies measured the risk of developing more than one treatment complication. Due to differences in study designs and populations, it is difficult to directly compare studies and not meaningful to calculate summary estimates. In addition to focusing on randomized clinical trials and well-designed population based studies, future research should adopt standardized methodologies and should measure the risk of developing more than one treatment complication.

Effect of moxidectin selection on the genetic variation within Cylicocyclus nassatus based on amplified fragment length polymorphism (AFLP)

Cyathostomins are among the most important intestinal nematodes of horses, yet, the literature on the molecular genetics of these worms is scarce. In this study, the technique of amplified fragment length polymorphism (AFLP) was applied to study the genetic diversity as well as to determine the effect of moxidectin selection on the population genetic diversity for Cylicocyclus nassatus, one of the most common cyathostomin species. Genomic DNAs from 30 individual male worms were used from each of two populations: an avermectin-milbemycin (AM)-naive population (Population-S) and a population derived from Population-S following 21 treatments with moxidectin (Population-Mox). Three selective primer pairs were used for each worm, yielding a total of 229 AFLP markers. Calculation of average pair wise Jaccard indices revealed a high degree of genetic variation within both populations using all three primer combinations. In addition, selection by moxidectin during a 3-year period caused a significant decrease in the level of genetic diversity as evidenced by analysis of AFLP markers for two primer combinations but not for the third. A dendrogram of relationships among individuals based on AFLP markers did not show a clear classification of individuals in separate groups. It was concluded that a high degree of genetic intrapopulation variation exists in C. nassatus and that moxidectin selection has a significant effect on the genetic composition of C. nassatus.

Isolation and characterisation of a beta tubulin isotype 2 gene from two species of cyathostomin

This study describes the isolation and characterisation of beta tubulin isotype 2 cDNA sequences from two common species of cyathostomin, Cylicocyclus nassatus and Cyathostomum catinatum. The full-length cDNAs for these species were 1709 and 1753 bp in length, respectively, including 1350 bp of sequence inferred to encode 450 amino acids of peptide sequence. They had greatest identity with previously characterised isotype 2 sequences from Trichostrongylus colubriformis, Cooperia oncophora and Haemonchus contortus (96% for C. nassatus and 95% for C. catinatum), and grouped together with these sequences in phylogenetic analysis. Both cyathostomin beta tubulin isotype 2 sequences contained the isotype-specific carboxyl terminal region described previously in other nematode species. Alignment with beta tubulin isotype 1 proteins from other trichostrongyloids, indicated 95 and 94% identity for the isotype 2 sequences of C. nassatus and C. catinatum, respectively. This comparison revealed 14 isotype-specific amino acid substitutions. Also, 2605 bp of beta tubulin isotype 2 genomic DNA sequence were isolated from C. nassatus. Comparison with the previously published isotype 1 gene of C. nassatus indicated differences in genomic organisation between the two isotypes. Reverse transcriptase (RT)-polymerase chain reaction analysis revealed constitutive temporal expression of beta tubulin isotype 1, whilst isotype 2 appeared to be developmentally expressed, with transcripts detected only in RNA derived from adult parasites.

Bermudagrass management in the Southern Piedmont USA. V: Gastrointestinal parasite control in cattle

Parasite-free pastures would improve cattle health and performance, resulting in possible economic return to producers. Our objective was to determine the effect of a single series of anthelmintic treatment of steers prior to stocking on Coastal bermudagrass pastures, during five consecutive summers, on the parasite burden in cattle. The site for this experiment had been conventionally cropped for several decades, with no exposure to cattle, and would be expected to be relatively free of nematode larvae. The experimental design was a randomized complete block (landscape features) with a split plot arrangement of treatments where main plots were pasture fertilization treatments (mineral, clover plus mineral, and broiler litter) and split plots were low and high forage mass. Anthelmintic treatment included pour-on ivermectin on day -21, albendazole on day -7, and injectable ivermectin 48 h prior to stocking of pastures, with the cattle remaining in drylot during the 48-h period prior to being placed on the experimental paddocks. All steers received only one series of treatments during any given year. Yearling Angus steers (Bos taurus) were managed in a put-and-take grazing system with three "tester" steers assigned to each paddock and "grazer" steers added or removed at 28-day intervals. From 1994 to 1998, steers grazed the paddocks for a 140-day period from mid May until early October each year. Fecal samples for worm egg counts were obtained on day 0 and at 28-day intervals, thereafter. On all sampling days after day 0, samples were obtained only from tester animals. Over the 5-year period, the mean eggs per gram of feces (epg) gradually increased from 0 (following treatment) to a mean of 2.2 (range from 0.7 to 3.0) by the end of the grazing season (the last sampling date) in October. Although the epg were not zero, they were below threshold levels that would allow development of a parasite burden in cattle. In traditional management systems, cattle graze parasite-contaminated pastures; therefore, parasites negatively impact growth and productivity throughout the entire grazing period. Periodic anthelmintic treatments simply give a temporary reprieve from those parasitic infections. Conceptually, using the current grazing system, it should be possible to maintain these pastures in a parasite-free status indefinitely; however, from a drug resistance perspective, it would be most applicable in sod-based rotation systems where cattle graze from two to five years before land is returned to row-crops. By removing the effect of parasites, cattle can grow without the physiological constraints that gastrointestinal parasites place on appetite, digestion, nutrient utilization, and general well being.

Glycemia and the Quality of Well-Being in Patients with Diabetes

OBJECTIVES

To investigate the cross-sectional relationships among self-reported frequencies of symptomatic hyperglycemia and hypoglycemia, HbA1c, and symptoms in the Quality of Well-Being Self-Administered (QWB-SA), and to examine the associations among these measures of glycemia and health-utility scores.

METHODS

The study group included 1522 patients with diabetes who attended University of Michigan Health System clinics. Published studies were reviewed to identify symptoms in the QWB-SA that might be associated with measures of glycemia. Linear-regression analyses were performed to evaluate the strength of the associations among the frequency of self-reported measures of glycemia, QWB-SA symptoms, and QWB-SA-derived health-utility scores.

RESULTS

Frequency of hyperglycemic symptoms was associated with 3% of the variance in the QWB-SA-derived health-utility score in type-1 diabetes and with 5% of the variance in type-2 diabetes. Frequency of hypoglycemic symptoms was not associated with the QWB-SA-derived health-utility score in type-1 diabetes but was associated with 1% of the variance in type-2 diabetes. HbAlc levels were not significantly associated with QWB-SA-derived health-utility scores. After controlling for age, gender, and complications, frequency of hyperglycemic symptoms was significantly associated with QWB-SA-derived health-utility scores in type-1 and type-2 diabetes.

CONCLUSIONS

Reported frequency of hyperglycemic symptoms is associated with symptoms included in the QWB-SA and with QWB-SA-derived health-utility scores. The QWB-SA may be an appropriate measure to assess the health burden of hyperglycemia.

Validation of the FAMACHA© eye color chart for detecting clinical anemia in sheep and goats on farms in the southern United States

Recent studies on sheep and goat farms in the southern United States indicate that multiple-anthelmintic resistance in Haemonchus contortus is becoming a severe problem. Though many factors are involved in the evolution of resistance, the proportion of the parasite population under drug selection is believed to be the single most important factor influencing how rapidly resistance develops. Therefore, where prevention of resistance is an important parallel goal of worm control, it is recommended to leave a portion of the animals untreated. Recently, a novel system called FAMACHA was developed in South Africa, which enables clinical identification of anemic sheep and goats. When H. contortus is the primary parasitic pathogen, this system can be applied on the farm level to reduce the number of treatments administered, thereby increasing the proportion of the worm population in refugia. Since most studies validating the FAMACHA method have been performed in South Africa, it is important that the method be tested in other regions before its use is broadly recommended. We performed a validation study of FAMACHA by testing the system in sheep (n = 847) and goats (n = 537) of various breeds and ages from 39 farms located in Arkansas, Georgia, Louisiana, Florida, and the US Virgin Islands. The color of the ocular conjunctiva of all animals were scored on a 1-5 scale using the FAMACHA card, and blood samples were collected from each animal for determination of packed cell volume (PCV). Fecal samples were also collected from a majority of the animals tested for performance of fecal egg counts (FEC). Correlations between PCV and eye scores, PCV and FEC, and FEC and eye scores were all highly significant for both sheep and goats (P < 0.001). Data for both FAMACHA scores and PCV were evaluated using two separate criteria for anemia: eye score values of 3, 4 and 5 or 4 and 5, and PCV values of < or =19 or < or =15 were considered anemic. Specificity was maximized when eye score values of 4 and 5 were considered anemic and PCV cut off for anemia was < or =19, but sensitivity was low. In contrast, sensitivity was 100% for both sheep and goats when eye score values of 3, 4 and 5 were considered anemic and PCV cut off was < or =15, but specificity was low. In both sheep and goats, predictive value of a negative was greater than 92% for all anemia and eye score categories, and was greater than 99% for both eye score categories when an anemia cutoff of < or =15 was used. Predictive value of a positive test was low under all criteria indicating that many non-anemic animals would be treated using this system. However, compared to conventional dosing practices where all animals are treated, a large proportion of animals would still be left untreated. These data indicate that the FAMACHA method is an extremely useful tool for identifying anemic sheep and goats in the southern US and US Virgin Islands. However, further studies are required to determine optimal strategies for incorporating FAMACHA-based selective treatment protocols into integrated nematode control programs.

Evaluation of a larval development assay (DrenchRite®) for the detection of anthelmintic resistance in cyathostomin nematodes of horses

A larval development assay (LDA, DrenchRite) was evaluated to determine the effectiveness of this method in detecting anthelmintic resistance in cyathostomin nematodes of horses. A total of 15 horse farms from Georgia and South Carolina (USA) and Population S ponies from the University of Kentucky (USA) were included in this study. Nematode eggs were extracted from pooled fecal samples and placed into the wells of a DrenchRite plate for testing against thiabendazole (TBZ), levamisole (LEV) and 2 ivermectin (IVM) analogs (IVM-1, IVM-2). After a 7-day incubation larvae in each well were counted and data were analyzed by logistic regression. Resistance status of each farm for different drugs was determined in a separate study using a fecal egg count reduction test. LDA were performed on the 15 farms once, however, the Population S cyathostomins were assayed on 3 separate occasions to estimate the consistency of results between assays. Mean TBZ LC50 for oxibendazole resistant, suspected resistant and sensitive farms were 0.2015, 0.1625, and 0.1355 microM, respectively. For LEV, mean LC50 for PYR resistant, suspected resistant and sensitive farms were 1.590, 1.8018 and 1.4219 microM, respectively. All 15 farms had worms susceptible to IVM; mean LC50 for IVM-1 and for IVM-2 were 7.5727 and 87.9718 nM, respectively. A linear mixed model was fitted to the data to determine the relationship between LC50 and LC95 and resistance status for each farm. No meaningful relations were found. Consistency of assays varied between drugs, being best for TBZ and worst for LEV and IVM-1. All farms in this study had benzimidazole-resistant nematodes; therefore usefulness of DrenchRite for discriminating susceptibility versus resistance to this drug class could not be accurately assessed. Moreover, since all farms tested were sensitive to IVM and resistance to this drug class has not yet been reported in cyathostomins, it is not possible to assess accurately the usefulness of DrenchRite LDA for detecting IVM resistance at this time. Assay results for LEV suggest that LEV in a LDA does not yield data that is useful in estimating PYR efficacy in vivo. Based on results for PYR/LEV, the current high prevalence of benzimidazole resistance, no known cases of IVM resistance, and the sometimes extreme variation in results seen in many of the assays, DrenchRite LDA cannot be considered a useful tool for the diagnosis of resistance in cyathostomins of horses at present.

Capability of the nematode-trapping fungus Duddingtonia flagrans to reduce infective larvae of gastrointestinal nematodes in goat feces in the southeastern United States: dose titration and dose time interval studies

Infection with gastrointestinal nematodes, particularly Haemonchus contortus, is a major constraint to goat production in the southeastern United States. Non-anthelmintic control alternatives are needed due to increasing resistance of these nematodes to available anthelmintics. Two studies were completed in Central Georgia in August 1999, and April-May 2000, using Spanish does naturally infected with Haemonchus contortus, Trichostongylus colubriformis, and Cooperia spp. to evaluate effectiveness of nematode-trapping fungi as a biological control agent. In the first experiment, five levels of Duddingtonia flagrans spores were mixed with a complete diet and fed once daily to the does (three per treatment) in metabolism crates. The treatment concentrations were (1) 5 x 10(5), (2) 2.5 x 10(5), (3) 10(5), and (4) 5 x 10(4) spores per kilogram body weight (BW), and (5) no spores. Fungal spores were fed for the first 7 days of the 14-day trial, and fecal samples were collected daily from individual animals for analysis of fecal egg count and establishment of fecal cultures. Efficacy of the fungus at reducing development of infective larvae (L3) in the fecal cultures was evaluated. The mean reduction in L3 from day 2 of the treatment period until the day after treatment stopped (days 2-8) was 93.6, 80.2, 84.1, and 60.8% for animals given the highest to lowest spore doses, respectively. Within 3-6 days after termination of fungal spore feedings, reduction in L3 development was no longer apparent in any of the treated animals. In a second experiment, effectiveness of 2.5 x 10(5) spores of D. flagrans per kilogram BW fed to does every day, every second day, and every third day was evaluated. Reduction in L3 development by daily feeding was less in the second experiment than in the first experiment. Daily fungal spore feeding provided more consistent larval reduction than intermittant feeding (every second or third day). When fed daily under controlled conditions, D. flagrans was effective in significantly reducing development of L3 and appears to be an effective tool for biocontrol of parasitic nematodes in goats.

Methodological issues in evaluating measures of health as outcomes for COPD

The selection of an appropriate outcome measure depends on the aspect of the disease being addressed and the purpose of the study being conducted. The most fundamental property of any outcome is its ability to measure the biological variable under question. Other properties such as discriminative and evaluative abilities are also important. Specific outcomes measure a single biological variable, such as forced expiratory volume in one second or depression. The specificity of such measures is attractive but requires precise definition of what is being measured and why. Other, summative, outcomes are used to quantify the overall effect of a number of different biological processes. The simplest summative measures are global questions such as "How would you rate your health overall?" Others are complex with many items. If designed and used correctly, these questionnaires can provide an estimate of the overall impact of disease or response to therapy and an index of whether that response was clinically worthwhile. Standardisation of measurements is important to permit comparisons between patients and studies, which makes the measurement of an individual's "quality of life" difficult. The term "health-status measurement" may be better when referring to the use of standardised questionnaires. Utility-based measures help address concerns regarding clinical versus statistical improvement and place outcomes for chronic obstructive pulmonary disease treatment trials in the context of all healthcare treatments.

Comparison of German language versions of the QWB-SA and SF-36 evaluating outcomes for patients with prostate disease

BACKGROUND

The quality of well-being scale (QWB) and the Medical Outcome Study 36-item short form (SF-36) are alternative methods for measuring general health outcomes. Few studies compare these approaches against one another and no studies have compared German language versions.

METHOD

A German language version of the self-administered quality of well-being scale (QWB-SA) was developed using forward and back translation methods. The German QWB-SA and a German language version of the SF-36 were administered to clinical population groups with current diagnoses of prostate cancer, benign hyperplasia of the prostate, colon cancer, and rectal cancer. Data were obtained from four German clinics. In addition to the quality of life measures, data on cancer stage and disease state were obtained.

RESULTS

The QWB-SA and SF-36 were highly correlated. The QWB-SA was systematically related to disease state. Those with no symptomatic evidence had the highest scores followed by those who were stable with no metastatic disease and those with metastatic progression. Similar patterns were found for most SF-36 scales although the SF-36 failed to discriminate between those with no evidence of disease and those with stable disease without metastasis.

CONCLUSIONS

Both the QWB-SA and SF-36 perform as expected using German language translations. Although both measures differentiate patients with metastasis from those without symptoms, the QWB-SA better differentiated those with no evidence of disease from those with stable disease without metastasis.

Simulated effect of tobacco tax variation on Latino health in California

BACKGROUND

Over one fourth of the California population was Latino in 1999, and by 2015 Latinos are expected to be the single largest ethnic group in California. Patterns of smoking and nicotine dependence among Latino smokers may be quite different from those of smokers in other ethnic groups. In addition, Latino smokers may be more sensitive to cigarette prices. Therefore, the effect of an increase in cigarette excise taxes on Latino smoking prevalence may be quite large, and consequently the impact on Latino health may be proportionately greater than on population health in general.

METHODS

We simulated changes in Latino smoking, morbidity, mortality, and quality-adjusted life years (QALYs) that would result from a range of actual and proposed cigarette excise-tax increases using a range of cigarette price-elasticity estimates specific to Latino smokers. Monte Carlo simulation was used to generate confidence intervals.

RESULTS

Assuming a Latino price elasticity of demand for cigarettes of -1.0, reductions in Latino smoking resulting from an additional $0.50/pack tax would produce nearly 3000 Latino QALYs in California in 1999. Greater benefits would accrue each year, until a steady state relative to population size is reached 75 years after the program is initiated.

CONCLUSIONS

If Latino smokers are more responsive to changes in cigarette prices than other smokers, Latino smokers also stand to gain a disproportionate share of the health benefit from an excise tax increase.

Depression, visual acuity, comorbidity, and disability associated with age-related macular degeneration

OBJECTIVE

To examine (1) the prevalence of depressive disorders in community-dwelling adults with advanced age-related macular degeneration (AMD) and (2) the relationship in this population between depression, visual acuity, the number of comorbid medical conditions, disability caused by vision loss as measured by the National Eye Institute-Vision Function Questionnaire (NEI-VFQ) and the vision-specific Sickness Impact Profile (SIPV), and disability caused by overall health status as measured by the Sickness Impact Profile-68 (SIP).

DESIGN

Analysis of cross-sectional baseline data from a randomized clinical trial.

PARTICIPANTS

Participants were 151 adults aged 60 and older (mean age, 80 years) with advanced macular degeneration whose vision was 20/60 or worse in their better eye.

METHODS

Subjects were interviewed using measures of depression, disability, and chronic medical conditions. Visual acuity was obtained. Nonparametric correlation analyses and linear regression analyses were performed.

MAIN OUTCOME MEASURES

Structured Clinical Interview for DSM-IV (SCID-IV), Geriatric Depression Scale (GDS), NEI-VFQ, SIPV, and SIP.

RESULTS

Of the participants, 32.5% (n = 49) met SCID-IV criteria for depressive disorder, twice the rate observed in previous studies of community-dwelling elderly. Over and above depression (GDS), visual acuity aided in prediction of the level of vision-specific disability (NEI-VFQ and SIPV).

CONCLUSIONS

Depressive disorder is a significant problem for the elderly afflicted with advanced macular degeneration. Further research on psychopharmacologic and psychotherapeutic interventions for depressed AMD patients is warranted to improve depression and enhance functioning. Over and above depression, visual acuity aided in predicting vision-specific disability. Treatment strategies that teach patients to cope with vision loss should be developed and evaluated.

A randomized clinical trial of continuous versus intermittent dialysis for acute renal failure

BACKGROUND

Acute renal failure (ARF) requiring dialysis in critically ill patients is associated with an in-hospital mortality rate of 50 to 80%. The worldwide standard for renal replacement therapy is intermittent hemodialysis (IHD). Continuous hemodialysis and hemofiltration techniques have recently emerged as alternative modalities. These two therapies have not been directly compared.

METHODS

A multicenter, randomized, controlled trial was conducted comparing two dialysis modalities (IHD vs. continuous hemodiafiltration) for the treatment of ARF in the intensive care unit (ICU). One hundred sixty-six patients were randomized. Principal outcome measures were ICU and hospital mortality, length of stay, and recovery of renal function.

RESULTS

Using intention-to-treat analysis, the overall ICU and in-hospital mortalities were 50.6 and 56.6%, respectively. Continuous therapy was associated with an increase in ICU (59.5 vs. 41.5%, P < 0.02) and in-hospital (65.5 vs. 47.6%, P < 0.02) mortality relative to intermittent dialysis. Median ICU length of stay from the time of nephrology consultation was 16.5 days, and complete recovery of renal function was observed in 34.9% of patients, with no significant group differences. Despite randomization, there were significant differences between the groups in several covariates independently associated with mortality, including gender, hepatic failure, APACHE II and III scores, and the number of failed organ systems, in each instance biased in favor of the intermittent dialysis group. Using logistic regression to adjust for the imbalances in group assignment, the odds of death associated with continuous therapy was 1.3 (95% CI, 0.6 to 2.7, P = NS). A detailed investigation of the randomization process failed to explain the marked differences in patient assignment.

CONCLUSIONS

A randomized controlled trial of alternative dialysis modalities in ARF is feasible. Despite the potential advantages of continuous techniques, this study provides no evidence of a survival benefit of continuous hemodiafiltration compared with IHD. This study did not control for other major clinical decisions or other supportive management strategies that are widely variable (for example, nutrition support, hemodynamic support, timing of initiation, and dose of dialysis) and might materially influence outcomes in ARF. Standardization of several aspects of care or extremely large sample sizes will be required to answer optimally the questions originally posed by this investigation.

Anthelmintic resistance on goat farms in Georgia: efficacy of anthelmintics against gastrointestinal nematodes in two selected goat herds

Gastrointestinal nematode (GIN) parasitism is a major constraint to production of goats in the southeastern United States. The conventional method of control used by producers in this region is frequent use of anthelmintics during the warm season. Overuse of anthelmintics has led to an increase in the incidence of anthelmintic resistance in many parts of the world, but data on prevalence of anthelmintic resistance in GIN of goats in the southeastern United States are very limited. To address this issue, anthelmintic efficacy was determined in goat herds at the Fort Valley State University, Agricultural Research Station (FVSU-ARS) and the University of Georgia, College of Veterinary Medicine (UGA-CVM) using fecal egg count reduction (FECR) tests and DrenchRite((R)) larval development assays (LDA). At FVSU-ARS, 2-year-old Spanish goat does were randomly allocated to one of nine different treatment groups (n = 10): albendazole (ABZ; 20mg/kg body weight (BW)), fenbendazole (FBZ; 20mg/kg BW), ivermectin (IVM; 0.4 mg/kg BW), doramectin (DRM; 0.4 mg/kg BW), moxidectin (MOX; 0.4 mg/kg BW), levamisole (LEV; 12 mg/kg BW), morantel tartrate (MOR; 10mg/kg BW), a combination of IVM (0.4 mg/kg BW) and ABZ (20 mg/kg BW), and untreated controls. At UGA-CVM, goats were randomly allocated to one of five different treatment groups (n = 8): ABZ (20 mg/kg BW), IVM (0.4 mg/kg BW), MOX (0.4 mg/kg BW), LEV (12 mg/kg BW), and untreated controls. All drugs in both experiments were administered orally. Anthelmintic efficacy was calculated by comparing 14-day post-treatment FEC of treated and control animals, and percent reductions were interpreted using the World Association for the Advancement of Veterinary Parasitology guidelines for resistance. For the LDA, nematode eggs were isolated from pooled fecal samples of untreated control goats in each herd and used to perform DrenchRite((R)) assays. In the FVSU-ARS herd, MOX, LEV, the combination of IVM and ABZ, IVM, DRM, ABZ, MOR, and FBZ reduced FEC by 100, 91, 88, 78, 76, 62, 48, and 10%, respectively. In the UGA-CVM herd, MOX, LEV, ABZ and IVM, reduced FEC by 100, 94, 87, and 0%, respectively. In both herds moxidectin was the only drug tested that was fully effective. Results of the LDA were in agreement with results of the FECR tests for both herds. These data demonstrate the presence of GINs resistant to all three major anthelmintic classes in both goat herds.

Prevalence and clinical implications of anthelmintic resistance in cyathostomes of horses

OBJECTIVE

To determine the prevalence and clinical implications of anthelmintic resistance in cyathostomes of horses.

DESIGN

Prospective study.

ANIMALS

80 horses on 10 farms in a 5-county region of northeast Georgia.

PROCEDURE

On each farm, horses were stratified in descending order according to pretreatment fecal egg count (FEC), blocked into groups of 4, and then randomly assigned to 1 of 4 treatment groups: no treatment (controls), and treatment with pyrantel pamoate, fenbendazole, or ivermectin. Fecal samples were collected 24 hours prior to treatment and 2, 4, and 6 weeks after treatment for determination of FEC. Mean percentage of reduction in FEC was then calculated for each treatment group. For horses from each farm, the efficacy of each anthelmintic was categorized on the basis of mean percentage of reduction in FEC at 2 weeks after treatment (< 80% reduction = ineffective; 80 to 90% reduction = equivocal; and > 90% reduction = effective).

RESULTS

Pyrantel pamoate was effective at reducing FEC in horses from 7 farms, ineffective in horses from 2 farms, and equivocal in horses from 1 farm. Fenbendazole was ineffective at reducing FEC in horses from 9 farms and equivocal in horses from 1 farm. Ivermectin was effective at reducing FEC in horses from all 10 farms.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that cyathostome resistance to fenbendazole is highly prevalent, and resistance to pyrantel pamoate is high enough to warrant concern. Resistance to ivermectin was not detected. On the basis of these data, it appears that ivermectin continues to be fully effective in horses. However, too few farms were used in this study to determine the prevalence of cyathostome resistance to ivermectin. Therefore, the efficacy of ivermectin should continue to be monitored closely.

The evaluation of two methods to facilitate shared decision making for men considering the prostate-specific antigen test

OBJECTIVE

California law (Grant H. Kenyon Prostate Cancer Detection Act) requires physicians to inform all patients older than aged 50 years who receive a prostate examination about the availability of the prostate-specific antigen (PSA) test. Physicians are not given guidance on how this information should be presented. We sought to evaluate the effects upon PSA screening rates of informing patients about PSA testing by 2 different techniques.

DESIGN

Factorial comparison of discussion versus video formats for presenting information about the PSA test.

SETTING

Patients were recruited through the Health Appraisal screening program in the Department for Preventive Medicine, Kaiser Permanente, San Diego, Calif.

PARTICIPANTS

Male patients undergoing health appraisal screening participated in 1 of 4 groups providing information about PSA screening: usual care ( n=43), discussion about risks and benefits of PSA ( n=45), shared decision-making video ( n=46), or video plus discussion ( n=42). Participants were sequentially assigned to 1 of the 4 groups.

RESULTS

No significant differences in demographics or family history was demonstrated between the groups at the time of group assignment. Participants in the intervention groups rated the information as clear, balanced, and fair. There were significant differences in the number of men requesting a PSA test, with the highest rate in the usual care group (97.7%), followed by discussion (82.2%), video (60.0%), and video plus discussion (50.0%).

CONCLUSION

Providing information about PSA screening in the form of video or discussion is feasible and significantly alters PSA screening rates.

Health-related quality-of-life measure enhances acute treatment response prediction in depressed inpatients

BACKGROUND

Many nonbiological variables are reported to predict treatment response for major depression; however, there is little agreement about which variables are most predictive.

METHOD

Inpatient subjects (N = 59) diagnosed with current DSM-IV major depressive disorder completed weekly depressive symptom ratings with the Hamilton Rating Scale for Depression (HAM-D-17) and Beck Depression Inventory (BDI), and weekly health-related quality-of-life (HRQL) ratings with the Quality of Well-Being Scale (QWB). Acute responders were identified by a 50% decrease in HAM-D-17 score from baseline within 4 weeks of medication treatment. Predictor variables were initially chosen from a literature review and then tested for their association with acute treatment response.

RESULTS

An initial predictive model including age at first depression, admission BDI score, and melancholia predicted acute treatment response with 69% accuracy and was designated as the benchmark model. Adding the admission QWB index score to the benchmark model did not improve the prediction rate; however, adding the admission QWB subscales for physical and social activity to the benchmark model significantly improved acute treatment response prediction to 86% accuracy (p = .001).

CONCLUSION

In addition to being designed for use in cost-effectiveness analyses, the QWB subscales appear to be useful HRQL variables for predicting acute inpatient depression treatment response.

Economic analysis of lung volume reduction surgery as part of the National Emphysema Treatment Trial. NETT Research Group

BACKGROUND

In today's cost-conscious health care environment, obtaining timely and accurate economic information regarding new medical technologies has become extremely important. The National Emphysema Treatment Trial, a multicenter, randomized controlled trial of lung volume reduction surgery (LVRS) plus medical therapy, versus medical therapy for patients with severe emphysema, includes a parallel cost-effectiveness analysis.

METHODS

The analysis is designed to determine the cost-effectiveness of LVRS versus medical therapy for those who are eligible for the procedure. After describing theoretical foundations of cost-effectiveness analysis as they apply to this study, we describe the economic and quality of life data that are being collected alongside the clinical trial, methods of analysis, and approach to presenting the results.

RESULTS

The cost-effectiveness of LVRS relative to medical therapy will be presented as costs per quality-adjusted life years gained.

CONCLUSIONS

This analysis will provide timely economic data that can be considered alongside the clinical results of the National Emphysema Treatment Trial. As one of the largest clinical trials to include a parallel, prospective cost-effectiveness analyses, this study will also provide valuable practical information about conducting an economic analysis alongside a multicenter clinical trial.

Simulated effect of tobacco tax variation on population health in California

OBJECTIVES

This study simulated the effects of tobacco excise tax increases on population health.

METHODS

Five simulations were used to estimate health outcomes associated with tobacco tax policies: (1) the effects of price on smoking prevalence; (2) the effects of tobacco use on years of potential life lost; (3) the effect of tobacco use on quality of life (morbidity); (4) the integration of prevalence, mortality, and morbidity into a model of quality adjusted life years (QALYs); and (5) the development of confidence intervals around these estimates. Effects were estimated for 1 year after the tax's initiation and 75 years into the future.

RESULTS

In California, a $0.50 tax increase and price elasticity of -0.40 would result in about 8389 QALYs (95% confidence interval [CI] = 4629, 12,113) saved the first year. Greater benefits would accrue each year until a steady state was reached after 75 years, when 52,136 QALYs (95% CI = 38,297, 66,262) would accrue each year. Higher taxes would produce even greater health benefits.

CONCLUSIONS

A tobacco excise tax may be among a few policy options that will enhance a population's health status while making revenues available to government.

Fasciola hepatica: a review of the economic impact in cattle and considerations for control

To understand the rationale behind recommended control programs for liver flukes in cattle, the economic impact and the complex life cycle of Fasciola hepatica need to be appreciated. Fluke-infected cattle rarely demonstrate clinical disease, but subclinical impairment of feed efficiency, growth, and fertility can have an important impact on productivity. Although the precise benefit from controlling liver flukes is unknown due to the inherent variability between studies, most investigations demonstrate a considerable economic advantage to treatment. In addition, recent studies have demonstrated that liver flukes may cause a decrease in host fertility by altering normal metabolism and/or balance of sex hormones. This review focuses on these issues and how to best use available drugs to implement optimal fluke control programs.

Informed adherence: the need for shared medical decision making

Screening tests for colon cancer, breast cancer, and elevated serum cholesterol are widely advocated and included in some practice guidelines. Failure to complete these tests is regarded as patient noncompliance. The purpose of this paper is to review noncompliance with screening tests from the perspective of a traditional biomedical model and an outcomes model. According to the traditional biomedical model, compliance with screening tests is necessary to identify disease at an early stage and to initiate treatment. In contrast, the outcomes model argues that patients and providers should engage in activities that maximize benefit from the patient's perspective. Screening may lead to significant increases in case identification and in treatment rates. However, screening might also identify "pseudodisease," defined as disease that is not clinically important. For some diagnostic tests, cases of pseudodisease far exceed cases of clinically meaningful disease. The outcomes model suggests shared medical decision making in which uncertainties surrounding tests are disclosed to patients. Using information about the risks and expected health outcomes of screening and treatment, patients can participate in decisions about their own health care. Control Clin Trials 2000;21:233S-240S

Assessing the impact of migraine on health-related quality of life: An additional use of the quality of well-being scale-self-administered

OBJECTIVES

To compare the interviewer-administered Quality of Well-being Scale (QWB) with a self-administered form (QWB-SA) for patients with migraine, and to compare the health status of migraineurs to other medical populations.

BACKGROUND

With the increasing need to document the cost-effectiveness of treatment for migraine, limitations with both the Medical Outcomes Study Short Form-36 items and the QWB have been an impediment to research using cost-effectiveness as an outcome. Demonstrating the sensitivity of an alternative instrument which addresses these limitations would facilitate cost-effectiveness analyses on treatments for migraine.

METHODS

Eighty-nine adults (87% women) known to suffer from migraine were asked to complete both the interviewer-administered QWB and the self-administered version (QWB-SA) on three occasions. The first occasion was on a day when no migraine was experienced in the previous 7 days. The second and third assessments were completed within 48 hours of the onset of a migraine.

RESULTS

While both the QWB and the QWB-SA successfully distinguished migraine from nonmigraine days, more migraines were reported on the QWB-SA. Overall, both instruments showed similar patterns of patient dysfunction during a migraine attack. Each component of the QWB-SA successfully distinguished migraine from nonmigraine days, and the QWB-SA showed a linear sensitivity to pain intensity and disability during a migraine episode. Both instruments are able to detect a migraine's effect on multiple domains of quality of life. Study participants scored significantly lower on the QWB-SA during a migraine episode than several comparison medical populations.

CONCLUSIONS

The QWB and the QWB-SA appear to have sensitivity to migraine severity, and the ability to quantitate an effect in multiple quality-of-life domains. Both measures can be used to calculate quality-adjusted life-years, thus facilitating cost-effectiveness and health policy work in this important clinical area.

Validity and interpretation of preference-based measures of health-related quality of life

Utilities are numeric measurements that reflect an individual's beliefs about the desirableness of a health condition, willingness to take risks to gain health benefits, and preferences for time. This report discusses the approaches to assess and compare the validity of methods used to assign utilities for cost-utility analysis. Threats to validity include construct underrepresentation and construct-irrelevant variance. Construct underrepresentation occurs when a stimulus presented to a judge fails to fully represent the depth and complexity of information required in actual judgments. Construct-irrelevant variation occurs when factors irrelevant to preferences influence measurements of utilities. Among several factors that cause construct-irrelevant variation are cognitive abilities, numeracy skills, emotions and prejudices, and the elicitation procedure. Commonly used elicitation methods (visual-analog scales, time tradeoff, and standard gamble) capture different facets of utilities (desirableness of states, time preferences, and risk attitude) to different degrees. The validity of an elicitation protocol depends (1) on the degree to which its scaling method captures the relevant facets of utility and (2) on the degree to which measurements are influenced by construct-irrelevant variation. Discrete-state health index models provide an alternative to direct elicitation of utilities and work by attaching fixed preference weights to observable health states. The creation of discrete-state models with current technologies requires the adoption of strong assumptions about the scaling properties of utilities. Future research must refine methods of eliciting utilities and identify sources of construct-irrelevant variability that reduce the validity of utility assessments. Because of the impact of variation in techniques on measurements, we do not recommend the combination of utilities elicited with different protocols in cost-utility analysis and do not recommend the display of cost-utility ratios from different studies in comparison or "league" tables.

Age-related macular degeneration: a randomized clinical trial of a self-management intervention

The purpose of this study was to conduct a randomized clinical trial to assess whether a self-management group intervention can improve mood, self-efficacy, and activity in people with central vision loss due to age-related macular degeneration (AMD). Ninety-two elderly patients with AMD (average age = 79) from a university ophthalmology clinic were randomly assigned to the self-management intervention (n = 44) or to a wait-list (n = 48). All patients were legally blind in at least one eye. The intervention consisted of 6 weekly 2-hour group sessions providing education about the disease, group discussion, and behavioral and cognitive skills training to address barriers to independence. All participants eventually completed the intervention allowing pre-post comparisons for all patients. The battery of measures included the Profile of Mood States (POMS); Quality of Well-Being Scale; and assessments of self-efficacy, participation in activities, and use of vision aids. Participants' initial psychological distress was high (mean total POMS = 59.72) and similar to distress experienced by other serious chronic illness populations (e.g. cancer, bone marrow transplant). Analysis of covariance testing the primary hypothesis revealed that intervention participants experienced significantly (p = .04) reduced psychological distress (pre mean = 61.45; post mean = 51.14) in comparison with wait-list controls (pre mean = 57.72; post mean = 62.32). Intervention participants also experienced improved (p = .02) self-efficacy (pre mean = 70.16; post mean = 77.27) in comparison with controls (pre mean = 67.71; post mean = 69.07). Further, intervention participants increased their use of vision aids (p < .001; pre mean = 3.37, post mean = 6.69). This study demonstrates that a relatively brief behavioral intervention can substantially reduce psychological distress and increase self-efficacy in elderly adults experiencing vision loss due to macular degeneration. Self-management intervention appears to improve mood, self-efficacy, and use of vision aids, further enhancing the lives of poorly sighted individuals with AMD.

Two pathways to prevention

Health promotion and disease prevention programs are becoming important components of contemporary health care. There are at least 2 pathways to the enhancement of population health status through disease prevention. The first pathway requires the early diagnosis and treatment of disease. The second pathway promotes healthy lifestyles and disregards the requirement that a condition must be diagnosed before intervention is recommended. Data from several evaluations suggest that prevention efforts that rely on diagnosis have produced somewhat limited benefits, whereas primary prevention efforts may have substantial benefits. Current health policy places greater emphasis on secondary prevention. The objectives of improved population health might be better achieved by devoting relatively more resources to primary prevention through the promotion of healthy behaviors.

Quality of well being in patients with fibromyalgia

OBJECTIVE

The Quality of Well-being Scale (QWB) is a generic measure of health related quality of life that can be used for population monitoring, measurement of clinical outcomes, or cost effectiveness analysis. We report data on the validity of the QWB for patients with fibromyalgia (FM) and compare the effect of FM to that of other chronic diseases.

METHODS

The participants were 594 people recruited from a private health maintenance organization with a confirmed diagnosis of FM. The QWB was administered, along with measures of self-rated health status, physical functioning, pain, stiffness, anxiety, sleep, and depression. The QWB places levels of wellness on a continuum ranging from 0.0 (for death or the equivalent of being dead) to 1.0 (for optimum functioning without symptoms).

RESULTS

Patients with FM had mean QWB scores of 0.559 (SD 0.074), which is lower than scores reported for patients in most other chronic disease categories. QWB was significantly correlated with measures of physical functioning, stiffness, anxiety, depression, pain, and sleep quality.

CONCLUSION

Evidence supports the validity of the QWB for patients with FM. Patients with FM obtain lower scores on the QWB than patients with diagnoses of chronic obstructive pulmonary disease, rheumatoid arthritis, atrial fibrillation, advanced cancer, and several other chronic diseases. Although FM is generally considered a syndrome rather than a disease, substantial disability is experienced by people with this diagnosis.

Gender differences in quality-adjusted survival using a Health-Utilities Index

PURPOSE

Women live longer than men but experience high morbidity during later years. We attempt to represent life expectancy with adjustments for quality of life for men and women in the United States.

DATA SOURCES

Survival estimates were obtained from Vital Statistics of the United States Life Tables. Quality-of-life data were obtained for 12,220 participants, aged 32-85 years, in the 1982-1984 National Health and Nutrition Examination Survey I Epidemiologic Follow-Up Study (NHEFS).

METHOD

Using public data tapes, scores for the Health-Utilities Index (HUI) were imputed for NHEFS. These scores were calculated separately for men and women in the United States population and broken down by age. Using mortality data, the quality-adjusted life expectancy was calculated separately for men and women.

RESULTS

The current life expectancy among men aged 32 years was 39.45 years. For women aged 32 years it was 44.83 years, suggesting a 5.38 female life-expectancy advantage. The life expectancy, adjusted for quality of life, was 31.8 years for men versus 33.1 years for women. Adjustment for quality of life reduced the 5.38-year female advantage to 1.3 years.

CONCLUSIONS

Although women enjoy longer life expectancies than do men, this advantage is reduced when quality adjustments are used. The finding reflects high levels of morbidity among older women.

Shared decision making in clinical medicine: past research and future directions

Shared medical decision making is a process by which patients and providers consider outcome probabilities and patient preferences and reach a health care decision based on mutual agreement. Shared decision making is best used for problems involving medical uncertainty. During the process the provider-patient dyad considers treatment options and consequences and explores the fit of expected benefits and consequences of treatment with patient preferences for various outcomes. This paper reviews the literature on shared medical decision making. Several questions are considered. Although several studies suggest that patients do not want to be involved in decision making, these studies typically fail to separate decisions about technical aspects of treatment from preferences for outcomes. There is considerable evidence that patients want to be consulted about the impact of treatment. Studies on the acceptability of shared decision making for physicians have produced inconsistent results. Shared decision making is more acceptable to younger and better-educated patients. It remains unclear whether shared decision making requires expensive video presentations or whether the same results can be obtained with simpler methods, such as the decision board. We conclude that shared medical decision making is an important development in health care. More research is necessary to identify the effects of shared decision making on patient satisfaction and health outcomes. Further, more research is necessary in order to evaluate the most effective methods for engaging patients in decisions about their own health care.

Covariation of physical and mental symptoms across illnesses: results of a factor analytic study

OBJECTIVE

Chronic illnesses are associated with reports of symptoms, problems, and dysfunction along multiple dimensions. To determine if the dimensionality is disease-specific and whether physical and emotional symptoms are concomitant and inseparable aspects of the illness experience, we present a factor analysis of symptom and problem reports from five different chronic conditions.

METHOD

People with five different conditions participated in this study: multiple sclerosis (MS) (n = 263), non-insulin-dependent diabetes mellitus (n = 420), nonhead nonneck injury trauma (n = 852), and a group of terminal patients comprised of acquired immune deficiency syndrome (AIDS) (n = 99) and cancer (n = 74) patients. Participants were asked to complete the Quality of Well-Being Scale (QWB) and symptom items from the QWB were factor analyzed.

RESULTS

Both within each condition and across conditions, two factors accounted for the majority of the explained variance and could be described as an Observable Limitations factor and a Subjective Symptoms factor.

CONCLUSIONS

Our factor analyses suggest that physical and emotional symptoms covary and are common to different types of illness.

If diabetes is a public health problem, why not treat it as one? A population-based approach to chronic illness

It is increasingly acknowledged that diabetes and other chronic illnesses are major public health problems. Medicare and many managed health care organizations have recognized the enormous personal and societal costs of uncontrolled diabetes in terms of complications, patient quality of life, and health care system resources. However, the current system of reactive acute-episode focused disease care practiced in many settings does not adequately address this public health problem. An alternative proactive, population-based approach to chronic illnesses such as diabetes is proposed and illustrated. This multilevel systems approach addresses supportive and inhibitory social-environmental factors at multiple levels (personal, family, health care team, work, neighborhood, community). Key disciplines contributing to a population-based approach to diabetes include epidemiology, behavioral science, health care services, public health, health economics, and quality of life professions. Current and potential contributions of each of these disciplines are illustrated and an integrative, population-based systems approach to diabetes management and prevention of complications is proposed. This approach is also seen as applicable to other chronic illnesses.