Biomedical subjects

Andrew J Vickers

Publications and source records attributed to Andrew J Vickers.

43 records · Page 3Linked to original sources

PubMed2002

Immediate effects of dry needling and acupuncture at distant points in chronic neck pain: results of a randomized, double-blind, sham-controlled crossover trial.

To evaluate immediate effects of two different modes of acupuncture on motion-related pain and cervical spine mobility in chronic neck pain patients compared to a sham procedure. Thirty-six patients with chronic neck pain and limited cervical spine mobility participated in a prospective, randomized, double-blind, sham-controlled crossover trial. Every patient was treated once with needle acupuncture at distant points, dry needling (DN) of local myofascial trigger points and sham laser acupuncture (Sham). Outcome measures were motion-related pain intensity (visual analogue scale, 0-100 mm) and range of motion (ROM). In addition, patients scored changes of general complaints using an 11-point verbal rating scale. Patients were assessed immediately before and after each treatment by an independent (blinded) investigator. Multivariate analysis was used to assess the effects of true acupuncture and needle site independently. For motion-related pain, use of acupuncture at non-local points reduced pain scores by about a third (11.2 mm; 95% CI 5.7, 16.7; P = 0.00006) compared to DN and sham. DN led to an estimated reduction in pain of 1.0 mm (95% CI -4.5, 6.5; P = 0.7). Use of DN slightly improved ROM by 1.7 degrees (95% CI 0.2, 3.2; P = 0.032) with use of non-local points improving ROM by an additional 1.9 degrees (95% CI 0.3, 3.4; P = 0.016). For patient assessment of change, non-local acupuncture was significantly superior both to Sham (1.7 points; 95% CI 1.0, 2.5; P = 0.0001) and DN (1.5 points; 95% CI 0.4, 2.6; P = 0.008) but there was no difference between DN and Sham (0.1 point; 95% CI -1.0, 1.2; P = 0.8). Acupuncture is superior to Sham in improving motion-related pain and ROM following a single session of treatment in chronic neck pain patients. Acupuncture at distant points improves ROM more than DN; DN was ineffective for motion-related pain.

Acupuncture Analgesia↗

PubMed2002

Placebo controls in randomized trials of acupuncture.

Considerable intellectual and practical effort has been expended on designing and evaluating placebo controls in acupuncture studies. Somewhat less attention has been paid to the question: Why use a placebo in a randomized trial of acupuncture? This is partly because placebo controls have generally been seen as an inherent part of randomized trial methodology. As a result, most acupuncture trials have included a placebo-control group. A large number of different placebo techniques have been used in these trials. The design and choice of placebo techniques has typically depended on purely theoretical considerations, without empirical validation of physiological inactivity and psychological credibility. Principles can be developed for deciding whether to use placebo or another form of control in a randomized trial. These include issues of ethics, practicality and methodology. Such principles apply regardless of the intervention; they can and should be applied to acupuncture research.

Acupuncture Therapy↗

PubMedDate not supplied

Incorporating predictions of individual patient risk in clinical trials.

A risk prediction model is a statistical technique that gives a predicted probability of a certain event for an individual patient. Prediction models outperform the traditional risk classification systems that work by assigning patients into risk groups based on the presence or absence of particular risk factors, such as stage of disease. As such, risk prediction models have a number of important possible uses in clinical trials. For Phase II studies, prediction models can help adjust comparisons with historical control groups for differences in case mix. For Phase III studies, prediction models can ensure that accrued patients are at sufficiently high risk. This improves statistical power and avoids unethical inclusion of low-risk patients. We also propose that prediction models could potentially be used for applying the results of Phase III trials to individual patients. Clinical decisions could be informed by individualized estimates of treatment benefit, rather than by average treatment effects.

Clinical Trials, Phase III as Topic↗

PubMedDate not supplied

Statistical reanalysis of four recent randomized trials of acupuncture for pain using analysis of covariance.

OBJECTIVES: Acupuncture has been promoted for the treatment of chronic pain. Though many randomized trials have been conducted, these have been criticized for deficiencies of methodology, acupuncture technique, and sample size. Somewhat less emphasis has been placed on methods of statistical analysis. This paper describes 4 recent randomized trials of acupuncture for musculoskeletal or headache pain. Each trial used statistical methods that did not adjust for baseline pain scores and were thus of suboptimal power. The objective of this study is to reanalyze the trials using analysis of covariance (ANCOVA). METHODS: Raw data for the 4 trials were obtained from the original authors. Data were reanalyzed by ANCOVA. RESULTS: For 2 trials--acupuncture versus placebo for chronic headache and acupuncture versus transcutaneous electric nerve stimulation for back pain--reanalysis did not change the conclusion of no difference between groups, but showed that clinically significant differences between groups could not ruled out. Reanalysis of a trial of acupuncture versus placebo for shoulder pain slightly strengthened the evidence of acupuncture effectiveness. Reanalysis of the fourth trial, which compared acupuncture to placebo acupuncture and massage for neck pain, reversed the results of the original paper: reanalysis found acupuncture to be effective and that its effectiveness could not be ascribed to a placebo effect. DISCUSSION: Future trials of acupuncture and other modalities for pain should use efficient statistical methods. ANCOVA is more efficient than unadjusted analysis where used appropriately.

Acupuncture↗

PubMedDate not supplied

Double-blind, placebo-controlled, randomized trial of granulocyte-colony stimulating factor during postoperative radiotherapy for squamous head and neck cancer.

UNLABELLED: To evaluate the ability of granulocyte-stimulating factor to decrease mucositis during postoperative radiotherapy for stage II-IV squamous head and neck cancer in a randomized, double-blind, placebo-controlled trial. METHODS: After undergoing complete resection, patients were randomized to receive granulocyte-colony stimulating factor or placebo by daily subcutaneous injection during radiotherapy (63 Gy, 1.8 Gy/day). Patients undergoing prior radiotherapy or chemotherapy were excluded from the study. The primary outcome was the need for percutaneous endoscopic gastrostomy placement. Severity of mucositis was a secondary outcome. RESULTS: Forty-one patients were enrolled (132 planned). The study closed after slow accrual. Patient characteristics were as follows (granulocyte-colony stimulating factor vs placebo): median age, 59 versus 54 years; pT4, 16% versus 23%; pN2/3, 68% versus 59%; stage IV, 79% versus 68%. Forty patients were evaluable for planned outcomes. Patients in the granulocyte-colony stimulating factor arm showed trends toward lower rates of percutaneous endoscopic gastrostomy placement (0% vs 14%, P = 0.2) and severity of mucositis (P = 0.13), and had shorter mean radiotherapy duration (48.4 +/- 4.32 days vs 51.6 +/- 1.84 days, P = 0.005). Overall survival was significantly greater in the granulocyte-colony stimulating factor arm (hazard ratio, 0.37; P = 0.037). DISCUSSION: Granulocyte-colony stimulating factor during radiotherapy was feasible and led to significantly shorter radiotherapy duration and trends toward less percutaneous endoscopic gastrostomy placement and mucositis. The unanticipated improvement in survival outcomes warrants further hypothesis-driven investigation and validation.

Aged↗

PubMedDate not supplied

Analysis of variance is easily misapplied in the analysis of randomized trials: a critique and discussion of alternative statistical approaches.

Analysis of variance (ANOVA) is a statistical method that is widely used in the psychosomatic literature to analyze the results of randomized trials, yet ANOVA does not provide an estimate for the difference between groups, the key variable of interest in a randomized trial. Although the use of ANOVA is frequently justified on the grounds that a trial incorporates more than two groups, the hypothesis tested by ANOVA for these trials--"Are all groups equivalent?"--is often scientifically uninteresting. Regression methods are not only applicable to trials with many groups, but can be designed to address specific questions arising from the study design. ANOVA is also frequently used for trials with repeated measures, but the consequent reporting of "group effects," "time effects," and "time-by-group interactions" is a distraction from statistics of clinical and scientific value. Given that ANOVA is easily misapplied in the analysis of randomized trials, alternative approaches such as regression methods should be considered in preference.

Analysis of Variance↗

PubMedDate not supplied

Decision curve analysis: a novel method for evaluating prediction models.

BACKGROUND: Diagnostic and prognostic models are typically evaluated with measures of accuracy that do not address clinical consequences. Decision-analytic techniques allow assessment of clinical outcomes but often require collection of additional information and may be cumbersome to apply to models that yield a continuous result. The authors sought a method for evaluating and comparing prediction models that incorporates clinical consequences,requires only the data set on which the models are tested,and can be applied to models that have either continuous or dichotomous results. METHOD: The authors describe decision curve analysis, a simple, novel method of evaluating predictive models. They start by assuming that the threshold probability of a disease or event at which a patient would opt for treatment is informative of how the patient weighs the relative harms of a false-positive and a false-negative prediction. This theoretical relationship is then used to derive the net benefit of the model across different threshold probabilities. Plotting net benefit against threshold probability yields the "decision curve." The authors apply the method to models for the prediction of seminal vesicle invasion in prostate cancer patients. Decision curve analysis identified the range of threshold probabilities in which a model was of value, the magnitude of benefit, and which of several models was optimal. CONCLUSION: Decision curve analysis is a suitable method for evaluating alternative diagnostic and prognostic strategies that has advantages over other commonly used measures and techniques.

Decision Support Techniques↗