Letters to the Editor / Journal of Clinical Epidemiology 67 (2014) 354e358

February 27, 2013), the RCT [1] used only a single patch per patient even when two or three patches would be required to cover all the rib fractures and assumed that covering some but not all the rib fractures would result in a significantly lower narcotic dosage within the first 72 hours. This assumption was not logical because rib fracture pain lasts 6e8 weeks [2] and often gets worse during the first 72 hours after the fracture; the continuing pain of uncovered rib fractures required continuation of the narcotic analgesic dose being administered, confounding the RCT’s primary study hypothesis. Guidelines have been published to ensure that publications of RCTs clearly convey what was done so that readers can know that authors’ conclusions follow from what was done and what was found [5], but recent meta-analyses have reported that study authors often continue to confuse readers by drawing conclusions unsupported by the actual data [6]. Moreover, Glasziou et al. [7] reviewed 80 studies chosen for abstraction in EvidenceBased Medicine during 2005 and 2006 and reported that half omitted enough details that it would be impossible for clinicians to apply the studied treatments in clinical practice. Lidoderm patches provided significant pain relief in a caseecontrol study [2] and completely relieved my severe anterior rib fracture pain (while doing nothing for the pain of my posterior rib fractures, which were not covered, so I was unable to stop taking acetaminophen or reduce its dose). Patch treatment of rib fracture pain is one of the most effective therapies that I have observed during 35 years as a physician. No studies have been published regarding its effectiveness for clavicular fractures, but I believe it will work. One caveat: my body mass index (BMI) was 19.2 (low normal) and the patch may be more effective in patients with my body habitus than in a very obese patient because lidocaine can only penetrate so far through skin (eg, a depth of 8 mm was reported in one study) [8]. Neither of the two published studies reported evaluation of BMI as an explanatory variable [1,2]. Barry M. Farr Department of Medicine University of Virginia Health System PO Box 800473 Charlottesville, VA 22908, USA E-mail address: [email protected]

References [1] Ingalls NK, Horton ZA, Bettendorf M, Frye I, Rodriguez C. Randomized, double-blind, placebo-controlled trial using lidocaine patch 5% in traumatic rib fractures. J Am Coll Surg 2010;210:205e9. http://dx. doi.org:10.1016/j.jamcollsurg.2009.10.020. [2] Zink KA, Mayberry JC, Peck EG, Schreiber MA. Lidocaine patches reduce pain in trauma patients with rib fractures. Am Surg 2011;77: 438e42.

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[3] Concato J, Shah N, Horwitz RI. Randomized, controlled trials, observational studies, and the hierarchy of research designs. N Engl J Med 2000;342:1887e92. [4] Benson K, Hartz AJ. A comparison of observational studies and randomized, controlled trials. N Engl J Med 2000;342:1878e86. [5] Moher D, Schultz KF, Altman DG. The CONSORT statement: revised recommendations for improving the quality of reports of parallel-group randomized trials. Ann Intern Med 2001;134: 657e62. [6] Boutron I, Dutton S, Ravaud P, Altman DG. Reporting and interpretation of randomized controlled trials with statistically nonsignificant results for primary outcomes. JAMA 2010;303:2058e64. http://dx. doi.org:10.1001/jama.2010.651. [7] Glasziou P, Meats E, Heneghan C, Shepperd S. What is missing from descriptions of treatment in trials and reviews? BMJ 2008;14: 1472e4. http://dx.doi.org:10.1136/bmj.39590.732037.47. [8] Wallace MS, Kopecky EA, Ma T, Brophy F, Campbell JC. Evaluation of the depth and duration of anesthesia from heated lidocaine/tetracaine (Synera) patches compared with placebo patches applied to healthy volunteers. Reg Anesth Pain Med 2010;35:507e13. http:// dx.doi.org:10.1097/AAP.0b013e3181fa69b8. http://dx.doi.org/10.1016/j.jclinepi.2013.07.010

Blood counts: The epidemiology of chronic hepatitis B is reflected in routinely collected donor data To the Editor: Donated blood makes an incalculable contribution to the health and welfare of millions of humans every year. An estimated 108 million blood donations were collected in 2011, approximately half of which are collected in high-income countries [1]. To ensure safety of the blood supply, World Health Organization recommends that all blood donations should be screened for infection before use, with mandatory testing for human immunodeficiency virus (HIV), hepatitis B, hepatitis C, and syphilis [1]. First-time blood donors also provide important information regarding the prevalence of bloodborne pathogens including viral hepatitis and HIV, in what is generally a low-risk population. However, we are unaware of any previous research calculating the correlation between regional diversity in blood donor screening data and the estimated prevalence of bloodborne viruses in the wider community. A recent editorial in this journal highlighted the potential for innovative use of routinely collected data [2]. Population census information combined with birth country seroprevalence has been used to estimate the burden of chronic hepatitis B (CHB) in countries with a low overall prevalence, including the United States [3], the United Kingdom [4], and the Netherlands [5], in which birth in an endemic area is the primary determinant of CHB prevalence. Conflict of interest: None.

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Letters to the Editor / Journal of Clinical Epidemiology 67 (2014) 354e358

Table 1. HBV prevalence by state and territory in Australia based on census estimates [6] and first-time blood donor data [7], in decreasing order of blood donor prevalence

State or territory Northern Territory (NT) Victoria (VIC) New South Wales/ Australian Capital Territory (NSW/ACT)a Western Australia (WA) Queensland (QLD) South Australia (SA) Tasmania (TAS) Total Australia

Census-based estimates of chronic HBV prevalence (% of population)

Prevalence of HBV in first-time blood donors (number per 100,000 donors)

1.68 1.06 1.01

148.17 124.69 85.67

0.98 0.86 0.90 0.71 1.02

85.35 59.87 55.80 12.76 83.93

significantly with differences in CHB prevalence in the general community. If replicated elsewhere, the application of routinely collected blood donation data could be used to help validate other estimates of CHB prevalence (such as census-based methodologies), estimate geographic differences in the burden of disease across populations, and inform appropriate public health responses to CHB. Jennifer H. MacLachlan* Benjamin C. Cowie Epidemiology Unit Victorian Infectious Diseases Reference Laboratory 10 Wreckyn St, North Melbourne VIC 3051, Australia

Abbreviation: HBV, hepatitis B virus. a ACT included with NSW in blood donor data.

We recently published census-based estimates of CHB prevalence in Australia [6], suggesting that 218,000 Australians were living with CHB in 2011 (approximately 1% of the population). The burden of CHB varied notably between different regions, ranging from 0.7% in Tasmania to 1.7% in the Northern Territory [6]. We compared these results with routinely collected data on hepatitis B virus prevalence in first-time blood donors [7,8] for the years 2006e2011, which showed similar patterns by region (Table 1). The relationship between these estimates demonstrated significant correlation when analyzed by univariate linear regression (r2 Z 0.768, P Z 0.004; Fig. 1). These findings suggest that geographic differences in first-time blood donor prevalence of CHB correlate

Fig. 1. Scatter plot of HBV prevalence by state, based on census estimates and first-time blood donor data. HBV, hepatitis B virus; CHB, chronic hepatitis B; NT, Northern Territory; NSW, New South Wales; ACT, Australian Capital Territory; VIC, Victoria; WA, Western Australia; SA, South Australia; QLD, Queensland; TAS, Tasmania.

* Corresponding author. Tel.: þ61-(0)393422606; Fax: þ61-(0)393423930. E-mail address: [email protected]

References [1] World Health Organization. Blood safety and availability. Fact sheet No. 279. Geneva, Switzerland; World Health Organization; 2013. Available at http://www.who.int/mediacentre/factsheets/fs279/en/ index.html. Accessed July 15, 2013. [2] Tugwell P, Knottnerus JA, Idzerda L. Has the time arrived for clinical epidemiologists to routinely use ‘‘routinely collected data’’? J Clin Epidemiol 2013;66:699e701. [3] Kowdley KV, Wang CC, Welch S, Roberts H, Brosgart CL. Prevalence of chronic hepatitis B among foreign-born persons living in the United States by country of origin. Hepatology 2012;56: 422e33. [4] Hahne S, Ramsay M, Balogun K, Edmunds WJ, Mortimer P. Incidence and routes of transmission of hepatitis B virus in England and Wales, 1995-2000: implications for immunisation policy. J Clin Virol 2004;29:211e20. [5] Marschall T, Kretzschmar M, Mangen M-JJ, Schalm S. High impact of migration on the prevalence of chronic hepatitis B in the Netherlands. Eur J Gastroenterol Hepatol 2008;20:1214e25. [6] MacLachlan JH, Allard N, Towell V, Cowie BC. The burden of chronic hepatitis B virus infection in Australia, 2011. Aust N Z J Public Health 2013;37:416e22. Available at http://onlinelibrary. wiley.com/doi/10.1111/1753-6405.12049/full. Accessed July 15, 2013. [7] The Kirby Institute, The University of New South Wales and Australian Red Cross Blood Service. Transfusion-transmissible infections in Australia: 2012 surveillance report. 2012. Available at http://www. kirby.unsw.edu.au/sites/default/files/hiv/resources/TTI%20surveillance %20report%202012.pdf. Accessed July 15, 2013. [8] Lucky TTA, Seed CR, Keller A, Lee J, McDonald A, Ismay S, et al. Trends in transfusion-transmissible infections among Australian blood donors from 2005 to 2010. Transfusion 2013;53:2751e62. http://dx.doi.org/10.1111/trf.12144.

http://dx.doi.org/10.1016/j.jclinepi.2013.09.019

Blood counts: the epidemiology of chronic hepatitis B is reflected in routinely collected donor data.

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