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Quality of Life, Physical Disability, and Respiratory Impairment in Duchenne Muscular Dystrophy ¨ Malcolm Kohler, Christian F. Clarenbach, Lukas Boni, Thomas Brack, Erich W. Russi, and Konrad E. Bloch Pulmonary Division, Department of Internal Medicine, University Hospital of Zurich, Zurich, Switzerland ¨ ¨ Rationale: Duchenne muscular dystrophy (DMD) leads to progres- sisted ventilation via a tracheostomy or a mask had a positive sive, generalized paresis, and to respiratory failure in the second affect, and their life satisfaction was greater than anticipated by decade of life. The assumption that severe physical disability pre- their caregivers (6). In a more recent study, 13 of 23 patients with cludes an acceptable quality of life is common, but has not been DMD treated by nasal mask ventilation for chronic respiratory specifically evaluated in DMD. failure completed an HRQL questionnaire within 3 to 72 mo Objectives: The purpose of this study was to investigate the quality after starting assisted ventilation (3). Their health perception of life in relation to physical disability, pulmonary function, and the was superior to that of patients with chronic obstructive lung need for assisted ventilation in DMD. disease on noninvasive ventilation. Similarly, the mental compo- Methods: In 35 patients with DMD, aged 8–33 yr, we assessed physi- nent summary of the Short-Form 36 of the medical outcome cal disability by a score ranging from 9 (no disability) to 80 (com- plete dependence on care and technical aids), pulmonary function, questionnaire (SF-36) in 17 patients with DMD on noninvasive and health-related quality of life by Short-Form 36 of the medical ventilation was higher than corresponding values in patients with outcome questionnaire. chronic obstructive lung disease in another study (7). Although Measurements and Main Results: All patients required a wheelchair knowledge of the perceived quality of life in patients with chronic and help for dressing and eating. Fourteen patients were on long- illness requiring a high level of care is essential because it may term noninvasive positive-pressure ventilation. In ventilated pa- inﬂuence therapeutic decisions (8), a detailed analysis of quality tients, mean SD FVC was 12 10 % predicted, and the physical of life in patients with DMD in relation to their physical perfor- disability score was 65 7. Corresponding values in spontaneously mance, pulmonary function, and need for assisted ventilation breathing patients were 48 25 % predicted, and 51 7, respec- has not previously been performed. Therefore, we investigated tively (p 0.05 for both comparisons between groups). Short-Form HRQL, physical disability, and respiratory impairment in stable 36 physical function scores were massively reduced in both groups patients with DMD with and without requirement for assisted (1 2, and 0 0, respectively), but vitality, role-emotional, social ventilation. Some of the results of these studies have been re- function, and mental health scores were nearly normal (67–98), ported in the form of an abstract (9). and did not differ between groups. Conclusions: Quality of life in DMD is not correlated with physical impairment nor the need for noninvasive positive-pressure ventila- METHODS tion. The surprisingly high quality of life experienced by these se- Patients verely disabled patients should be taken into consideration when All patients with DMD living or attending school in a facility specialized therapeutic decisions are made. in the care of patients with muscular dystrophies, the Mathilde-Escher- Keywords: chronic respiratory failure; hypoventilation; muscular dis- Heim, Zurich, were prospectively enrolled. According to the concepts eases; noninvasive ventilation of the Swiss health care system, patients with advanced neuromuscular disease are generally cared for by their relatives at home as long as Duchenne muscular dystrophy (DMD) leads to progressive mus- feasible. Patients requiring a level of support that cannot be provided cle weakness of legs and arms, and respiratory and cardiac failure at home are admitted to one of the few institutions that offer services comparable to those of the Mathilde-Escher-Heim. The latter provides (1). Most patients become wheelchair-bound and dependent on schooling and lodging as needed. School graduates have the opportunity others for their daily activities during the second decade of life to undergo professional training in information technology using special (2). In advanced stages of the disease, chronic respiratory failure computer equipment. Some patients living in their parents’ homes are develops, and assisted mechanical ventilation is administered. brought in for daytime care. Others are full-time residents in the institu- Compared with historical controls, noninvasive positive-pressure tion, and live together in groups of three to ﬁve patients who share a ﬂat. ventilation (NIPPV) has increased the median survival of pa- They are attended by social workers, nursing staff, and physiotherapists. tients with DMD by several years to currently more than 25 yr In all patients, the diagnosis of DMD was based on standard criteria (3–5). Only a few studies have addressed the health-related qual- comprised of progressive symmetrical muscle weakness and other signs ity of life (HRQL) in patients with DMD. In an early investiga- and symptoms starting before the age of 5 yr, elevated serum creatinin tion, 80 severely disabled patients with DMD on long-term as- kinase activity, muscle biopsy and genetic analysis, and, in some, a family history consistent with X-linked recessive inheritance (10). Informed consent of patients and their parents was obtained. The protocol was approved by the ethics committee of the University Hospi- tal of Zurich. (Received in original form March 1, 2005; accepted in final form June 8, 2005) Supported by grants from The Lung League of Zurich, Switzerland. Measurements Correspondence and requests for reprints should be addressed to Konrad E. Bloch, A physical examination, including measurement of body weight and M.D., Pulmonary Division, Department of Internal Medicine, University Hospital body length, was performed. Body length was used for calculation of of Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland. E-mail: pneubloc@ ¨ ¨ body mass index and reference values of pulmonary function. It was usz.unizh.ch measured by a ﬂexible ruler ﬁtted along the contours of the body, from This article has an online supplement, which is accessible from this issue’s table the head, along the vertebral spine and the backside of the legs, to the of contents at www.atsjournals.org heels to account for kyphoscoliosis and leg contractures. Am J Respir Crit Care Med Vol 172. pp 1032–1036, 2005 Spirometry was performed in sitting position with a ﬂow meter Originally Published in Press as DOI: 10.1164/rccm.200503-322OC on June 16, 2005 attached to a ﬂanged rubber mouthpiece with the nose occluded (Vmax; Internet address: www.atsjournals.org SensorMedics, Yorba Linda, CA) (11). Sniff nasal pressure (SNIP) at Kohler, Clarenbach, Boni, et al.: Quality of Life in Muscular Dystrophy ¨ 1033 functional residual capacity and maximal expiratory pressure (MEP) tion. The VPAP II ventilator (ResMed, North Ride, Australia) at total lung capacity were measured (Pmax mouth pressure monitor; was used in the bilevel positive airway pressure S/T or T-mode, P.K. Morgan, Rainham-Gillingham, Kent, UK). Reference values for with inspiratory pressures of 12–22 cm H2O, expiratory pressures ages up to 17 yr (12, 13) and above (14, 15) were computed. Arterial of 3–5 cm H2O, and respiratory rate of 12–20 breaths/min. Six blood gas analysis was performed on a sample drawn in sitting position patients applied NIPPV during the night only, two patients dur- during spontaneous room-air breathing, with the exception of patients requiring continuous ventilatory support (AVL Medical Systems AG, ing the night and occasionally during the day ( 6 h), and six Diessenhofen, Switzerland). patients required NIPPV during the night and for more than 9 h Cardiac function was assessed clinically by ECG and echocardiogra- during the day. Four of these patients used the ventilator nearly phy. Cardiac involvement was assumed if there were rhythm or conduc- continuously over 24 h. They had a secondary, wheelchair- tion abnormalities, abnormal repolarization, a decreased left-ventricular mounted ventilator and a battery for backup during potential loss ejection fraction, or abnormal ventricular cavity dimensions or wall of electrical power. According to the course of DMD, patients on motion (16). NIPPV were older than the patients breathing spontaneously. Physical disability (i.e., the inability to perform activities of daily Patient characteristics and respiratory function are summarized living [ADL] and the dependence on support by others and on technical in Table 1. aids) was evaluated with a score speciﬁcally developed by one of the Spirometric volumes (FVC, FEV1) in patients not requiring authors (L.B.) for assessment of the course of illness in DMD. Some NIPPV were reduced to about one-half of the predicted value, aspects are similar to the index of independence in ADL described by Katz and colleagues (17). Disability was evaluated by assessing the whereas the corresponding values of patients on NIPPV were following eight aspects of daily life in a standardized way (see online only about one-tenth of the predicted value. In patients without supplement): mobility without technical aids, mobility with technical NIPPV, the reductions of maximal respiratory pressures (SNIP aids, transfers (e.g., from bed to wheelchair), static body control, and MEP) from predicted values were more pronounced than changes of body position, dressing, feeding, and breathing. Each aspect the reductions of lung volumes, but SNIP and MEP (% predicted was rated with up to 10 points, with higher scores reﬂecting greater value) were still signiﬁcantly greater than in patients requiring disability. The sum score of all eight domains was computed as a mea- NIPPV (Table 1). Spirometry and measurement of maximal sure of overall disability and of dependency on care; its maximal value respiratory pressures were not feasible in all patients due to was 80 points. The score had been prospectively applied over several ventilator dependency or difﬁculty in cooperation. years in a subset of the patients. These data are presented with the Cardiac evaluation had been performed clinically and by evaluation of all patients at the time of this study to illustrate that the score reﬂects the progressive disability in DMD. ECG in all 35 patients, and in 28 patients by echocardiography. The SF-36 was completed during an interview with each patient No cardiac abnormalities were found in 25 patients (71%). In (18). Transformed scores for each domain and the physical and mental 10 patients (29%), cardiomyopathy was suspected in the ECG, component summaries were computed (19). Reference values from and conﬁrmed by echocardiography (mean SD left-ventricular an age- and sex-matched U.S. population (18), and from a German ejection fraction, 36 12%). The age of patients with and with- population (20), were used for comparison. out cardiomyopathy was not statistically different (mean age, 21.3 5.8 vs. 18.2 5.7 yr; p 0.12). The scores of the SF-36 Data Analysis domains and of the disability scale were similar in patients with Data are expressed as means SD. Comparison of results between and without cardiomyopathy (p 0.05 for all comparisons; data groups was performed by unpaired t tests. A probability of p 0.05 not shown). was considered statistically signiﬁcant. Assuming a clinically relevant Disability and dependence on others and technical aids was difference in the mental component summary of the SF-36 question- assessed in 34 patients (Table 2). The disability sum scores were naire between ventilated and nonventilated patients of 5 or 10 points, plotted over time for 29 patients in whom at least two assess- the study was powered with 68% or 99%, respectively ( , 0.05). The ments, separated by at a least 1 yr, were available (Figure 1A). corresponding power to detect a relevant difference in the physical component summary was 78% (5-point difference) and 99% (10-point The relentlessly progressive course of the illness is evident. At difference). the time of the current evaluation of respiratory function and quality of life, patients on NIPPV were more disabled in each RESULTS evaluated aspect of daily living (Table 2) and had higher disability Thirty-ﬁve male patients with DMD were enrolled. Of these, 18 patients spent the nights in the home of their parents and at- tended school at the Mathilde-Escher-Heim, whereas 17 full- TABLE 1. ANTHROPOMETRICS AND RESPIRATORY FUNCTION time residents lived at the institution and went to school or worked there. All were wheelchair-bound due to advanced pare- Patients without NIPPV Patients on NIPPV sis of the legs and arms. Thoracolumbar scoliosis was apparent n Mean SD n Mean SD p Value in 34 patients (97%), and spinal stabilization surgery had been Age, yr 21 16.2 5.0 14 23.3 5.0 0.001 performed in 24 patients (69%). Some patients required intermit- BMI, kg/m2 21 22.3 6.4 14 16.0 6.9 0.01 tent treatment for musculoskeletal pain with nonsteroidal antiin- FVC, L 21 1.59 0.64 11 0.47 0.29 0.001 ﬂammatory drugs, but none received narcotic, psychotropic, or FVC, %pred 48 25 10 7 0.001 antidepressant drugs. FEV1, L 21 1.47 0.55 11 0.45 0.26 0.001 Fourteen patients were on chronic NIPPV by nasal or face FEV1, %pred 52 25 12 8 0.001 SNIP, cm H2O 15 32.3 14.2 10 13.4 5.2 0.001 mask. Long-term assisted ventilation had been initiated in pa- SNIP, %pred 28 13 11 4 0.001 tients with chronic hypoventilation (daytime PaCO2 50 mm Hg MEP, cm H2O 20 31.8 11.8 7 31.7 12.4 0.995 with appropriately compensated pH, or mean nocturnal transcu- MEP, %pred 16 8 9 4 0.024 taneous Pco2 50 mm Hg and oxygen saturation 90% during pH 16 7.39 0.02 12 7.37 0.04 0.117 5% of the night) and consistent symptoms, such as headaches, PaCO2, kPa 16 5.2 0.6 12 6.4 1.0 0.001 restless sleep, and excessive sleepiness (21). At the time of the PaO2, kPa 16 11.8 1.1 12 10.6 1.5 0.027 study, none of the patients met criteria for invasive ventilation Definition of abbreviations: BMI body mass index; MEP maximal expiratory via tracheostomy (uncontrollable airway secretions, repeated pressure; NIPPV noninvasive positive-pressure ventilation; SNIP sniff nasal aspiration ) or preferred this intervention over mask ventila- pressure. 1034 AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL 172 2005 TABLE 2. DISABILITY AND DEPENDENCE ON OTHERS AND TABLE 3. HEALTH-RELATED QUALITY OF LIFE TECHNICAL AIDS Patients Patients Patients Patients without NIPPV on NIPPV without NIPPV on NIPPV (n 21) (n 14) p Value (n 21) (n 13) p Value Physical functioning 1 2 0 0 0.083 Mobility without technical aids 9.6 0.6 10.0 0.0 0.004 Role-physical 68 29 71 29 0.724 Mobility with technical aids 5.2 1.0 7.0 1.2 0.001 Bodily pain 85 20 79 22 0.371 Transfer 8.4 2.1 9.9 0.6 0.005 General health 70 20 67 13 0.518 Static body control 7.5 1.2 8.7 1.0 0.004 Vitality 70 20 67 14 0.575 Change of body position 8.3 1.5 9.4 0.8 0.012 Social functioning 80 25 90 15 0.201 Getting dressed 7.2 1.3 8.5 1.0 0.003 Role-emotional 94 23 98 9 0.474 Feeding 2.3 1.2 4.9 2.5 0.003 Mental health 73 17 78 10 0.285 Breathing 2.1 0.4 6.6 2.3 0.001 Physical component summary 35 6 31 6 0.056 Disability sum score 50.6 7.2 64.9 7.0 0.001 Mental component summary 60 9 62 5 0.371 Reported health transition 49 6 45 11 0.194 Definition of abbreviation: NIPPV noninvasive positive-pressure ventilation. Values are mean SD. The maximal value of 10 in each domain indicates For definition of abbreviation, see Table 2. complete disability or dependence (see Table E1 in the online supplement). Values are mean SD. To compare the health proﬁle of patients with DMD with sum scores than patients without NIPPV (although there was values of a reference population, the scores of U.S. males, ages some overlap; Figure 1B). Due to the advanced generalized 18–24 yr (18), were subtracted from the measured scores in pa- paresis, the scores reﬂecting reductions in mobility, transfer, tients with DMD, and these differences are plotted in Figure 2. and body control were particularly high. The “mobility without Thus, this ﬁgure illustrates the deviations in the domain scores technical aid” scores of 10 and the “transfer” scores of 8 in of the studied population from the reference. German reference all patients on NIPPV reﬂected their need for a wheelchair and values (20) are also shown in Figure 2. Despite their greater their complete dependency on others for mobility. Similarly, limitation in pulmonary function and in ADL, the patients on they were all entirely unable to dress without help. The need NIPPV rated their HRQL similar to patients without NIPPV for assistance in eating and drinking was more variable (Table 2). (Table 3 and Figure 2). To further evaluate a potential effect As expected, HRQL was low in the SF-36 domains represent- of physical disability on HRQL, correlation analysis was per- ing physical function (the physical functioning scores were near formed on the SF-36 physical and mental component summaries zero) and, to a lesser extent, in domains representing problems versus the disability summary score. The Pearson correlation coef- with work and everyday activities as a result of physical health ﬁcients were r 0.326, p 0.06, and r 0.031, p 0.862, (moderate reduction in role-physical values; Table 3). Other aspects of well-being, such as general and mental health, emo- respectively. The correlation of the physical and mental compo- tions, social functioning, and pain, were not impaired according nent summaries versus FVC (% predicted) as a measure of to the patients’ judgment, and corresponding domain scores were respiratory impairment also revealed no statistically signiﬁcant close to the values observed in populations without chronic ill- correlation (Pearson correlation coefﬁcients, r 0.084, p 0.646, ness (Figure 2) (18). and r 0.268, p 0.138, respectively). The course of respira- tory impairment and HRQL as a function of age is illustrated in Figure 3. Figure 2. For each of the Short-Form 36 (SF-36) domains, the mean Figure 1. (A ) Disability scores of 29 patients, with at least two observa- deviation (and SD) from sex- and age-matched U.S. reference values tions obtained at yearly intervals before the main data acquisition for is displayed for 21 patients with Duchenne muscular dystrophy (DMD) the current study, clearly illustrate the progressive limitation in activities without NIPPV (open bars), and for 14 patients with NIPPV (hatched of daily living, and the dependence on others and technical aids. Lines bars). The dashed line represents the deviations of a German male refer- connect data in individual patients without noninvasive ventilation ence population (20) from the U.S. reference (18). BP bodily pain; (NIPPV; open circles) and with NIPPV (closed circles). (B ) The disability GH general health; MH mental health; PF physical functioning; scores at the time of assessment of pulmonary function and quality of life RE role-emotional; RP role-physical; SF social functioning; VT are plotted for patients without (open circles) and with NIPPV (closed circles). vitality. Kohler, Clarenbach, Boni, et al.: Quality of Life in Muscular Dystrophy ¨ 1035 DISCUSSION health and social functioning (Table 3). The scores in all SF-36 domains, except physical functioning, in the patients with DMD The main ﬁnding of our study is that patients with DMD of studied in the current investigation were also considerably higher various ages with advanced general muscle weakness and paresis (by 7 to 52 points) than corresponding scores we had obtained perceive a high quality of life despite their chronic progressive in patients with severe pulmonary emphysema undergoing lung illness, which makes them highly dependent on others and tech- volume reduction surgery (22). This may relate to better coping nical aids. Patients believe that the problems with ADL due to abilities in patients with DMD adapting themselves to a progres- their health status are relatively minor, although they are aware sive limitation since early childhood (Figure 4); patients with of their major limitation in physical functioning. With the excep- chronic obstructive lung disease may experience greater difﬁcul- tion of domains directly linked to the loss of muscle strength, ties in handling the limitations imposed by a chronic illness the HRQL of patients with DMD is independent of the degree acquired in adulthood. Another possibility is the very supportive of physical disability and respiratory impairment, and similar to and empathetic care given to the younger patients with DMD that in reference populations (18, 20). Our observations have by their parents and their caregivers. Furthermore, perception important clinical implications, as they contradict the still com- of health status, and expectations on achievable goals in life, mon assumption of a low HRQL of patients with advanced may differ between patients according to their illness and the disability and respiratory impairment, an assumption that may time of its manifestation. Mental retardation as a possible con- inﬂuence therapeutic decisions (8). founding factor was not speciﬁcally examined in the current This study provides the ﬁrst detailed account of the quality study, but was not prominent, as all patients attended at least of life in patients with DMD of various ages and degrees of primary school, and some underwent professional education in disability and respiratory impairment. The use of a generic information technology. HRQL might also be inﬂuenced by cer- HRQL questionnaire allows comparisons with other populations tain medications, but none of our patients received psychotropic, with and without chronic illnesses. Simonds and coworkers (3) antidepressant, or long-term analgetic drugs. An easy access to assessed HRQL with the SF-36 questionnaire in 13 patients with technical aids and activities that provide social contacts and DMD on nasal mask ventilation. Because no numeric data were independence might have contributed to the high HRQL per- provided, a quantitative comparison with our study is not feasible. ceived by the patients. Most of them own an electro-wheelchair, In a survey of HRQL in patients with chronic lung disease, kypho- and some own a cellular phone. They have the opportunity to scoliosis, and various neuromuscular diseases on domiciliary participate in electro-wheelchair hockey training and tourna- NIPPV, data on 17 patients with DMD were not reported sepa- ments (Figure 4), participate in excursions, holiday camps, and rately, with the exception of the SF-36 mental component sum- other leisure time activities. mary (7). The mean value of that component was 59.6, similar The lack of a correlation between physical disability scores, to the values of 60 and 62 that we found in patients without and lung function impairment, and SF-36 mental and physical compo- with NIPPV (Table 3). Compared with patients with chronic nent summaries in patients with DMD of a broad age range obstructive lung disease and kyphoscoliosis in the cited report (Figure 3) is in accordance with the notions discussed above. It (7), patients with DMD in the current study had much lower corroborates data from a longitudinal evaluation of 45 patients, physical functioning scores, but perceived less role limitation by aged 25–60 yr, with various distal and proximal muscular dystro- physical and mental problems, and scored higher in mental phies other than Duchenne, showing only moderate correlations between dependence with regard to ADL (17) and quality of life (23). The score we used for assessment of physical disability in DMD shares some similarities with the ADL, which was designed to evaluate disability and effects of rehabilitation in the elderly (17). However, our score incorporates some aspects typical of DMD (i.e., the consequences of progressive general- ized muscle weakness). The score tracked the course of illness Figure 3. Respiratory im- pairment, represented by FVC values, progresses with advancing age. (A ) The dashed line represents an exponential decay function (f a · e b·time). There is little variation in the physical as well as in the mental component summaries of the SF-36 questionnaire (B and C, re- spectively). Open circles, patients without NIPPV; closed circles, patients with NIPPV. Figure 4. Patients with DMD on wheelchairs playing land hockey, one of their favorite leisure time activities (reprinted by permission from Reference 25). 1036 AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL 172 2005 well, and asymptotically approached maximal values corre- 6. Bach JR, Campagnolo DI, Hoeman S. Life satisfaction of individuals with sponding to the complete loss of mobility, ventilator dependence, Duchenne muscular dystrophy using long-term mechanical ventilatory support. Am J Phys Med Rehabil 1991;70:129–135. and requirement of care by others (Figure 1). 7. Windisch W, Freidel K, Schucher B, Baumann H, Wiebel M, Matthys Evaluation of pulmonary function revealed that the SNIP H, Petermann F. Evaluation of health-related quality of life using the and MEP were relatively more reduced than spirometric lung MOS 36-Item Short-Form Health Status Survey in patients receiving volumes (Table 1), a ﬁnding consistent with an early impairment noninvasive positive pressure ventilation. Intensive Care Med 2003;29: of SNIP preceding reductions in vital capacity in motoneuron 615–621. 8. Gibson B. Long-term ventilation for patients with Duchenne muscular disease (24). dystrophy: physicians’ beliefs and practices. Chest 2001;119:940–946. In 80 severely disabled patients with DMD on long-term 9. Kohler M, Brack T, Clarenbach CF, Russi EW, Bloch KE. Quality of ventilation via tracheostomy or mask, the hardship associated life in patients with respiratory impairment due to muscular dystrophy. with chronic ventilator dependence was signiﬁcantly overesti- Eur Respir J 2004;24:3375. mated by health care professionals compared with the patients’ 10. Lin S, Liechti-Gallati S, Burgunder JM. New advances in muscular dystro- phy: an up-to-date diagnostic plan. Schweiz Med Wochenschr 1999; own assessments, demonstrating a relatively positive attitude and 129:1141–1151. health perception of patients with DMD, despite their physical 11. American Thoracic Society. Standardization of spirometry: 1994 update. dependence, and underlining the subjective nature of quality of Am J Respir Crit Care Med 1995;152:1107–1136. life (6). Although our cross-sectional study allows no deﬁnitive 12. Zapletal A, Samanek M, Paul T. Lung function in children and adoles- conclusion with regard to the effect of NIPPV on HRQL, the cents: methods, reference values. Prog Respir Res 1987;22:113–217. nearly normal values of SF-36 scores in domains other than 13. Stefanutti D, Fitting JW. Sniff nasal inspiratory pressure: reference values in Caucasian children. Am J Respir Crit Care Med 1999;159:107–111. physical function and physical role limitation (Table 3) suggest 14. Quanjer PH, Tammeling GJ, Cotes JE, Pedersen OF, Peslin R, Yernault that assisted ventilation does not adversely affect the perceived J-C. Lung volumes and forced ventilatory ﬂows: report working party health status. standardization of lung function tests European Community for Steel In conclusion, patients with DMD perceive a high HRQL and Coal. Eur Respir J Suppl 1993;16:5–40. independent of the degree of their physical disability, their respi- 15. Uldry C, Fitting JW. Maximal values of sniff nasal inspiratory pressures in healthy subjects. Thorax 1995;50:371–375. ratory impairment, and their dependence on NIPPV. Because 16. Finsterer J, Stollberger C. The heart in human dystrophinopathies. Cardi- medical professionals tend to underestimate the high HRQL ology 2003;99:1–19. perceived by the patients with DMD, these observations should 17. Katz S, Ford AB, Moskowitz RW, Jackson BA, Jaffe MW. Studies of be taken into consideration when decisions on mechanical venti- illness in the aged. The index of ADL: A standardized measure of biological and psychosocial function. JAMA 1963;185:914–919. lation and other life-sustaining therapies are made. 18. Ware JE Jr, Snow KK, Kosinski M, Gandek B. SF-36 health survey: Conflict of Interest Statement : None of the authors have a financial relationship manual and interpretation guide. Boston: The Medical Outcome Trust, with a commercial entity that has an interest in the subject of this manuscript. New England Medical Center; 1993. 19. Ware JE Jr, Kosinski M. SF-36 physical and mental health summary scales: a user’s manual. Boston: The Health Institute, New England References Medical Center; 1994. 1. Smith PE, Calverley PM, Edwards RH, Evans GA, Campbell EJ. Practi- 20. Kurth BM, Ellert U. The SF-36 questionnaire and its usefulness in popula- cal problems in the respiratory care of patients with muscular dystro- tion studies: results of the German Health Interview and Examination phy. N Engl J Med 1987;316:1197–1205. Survey 1998. Soz Praventivmed 2002;47:266–277. 2. Brooke MH, Fenichel GM, Griggs RC, Mendell JR, Moxley R, Florence 21. Make BJ, Hill NS, Goldberg AI, Bach JR, Criner GJ, Dunne PE. Mechan- ical ventilation beyond the intensive care unit: report of a consensus J, King WM, Pandya S, Robison J, Schierbecker J. Duchenne muscular conference of the American College of Chest Physicians. Chest 1998; dystrophy: patterns of clinical progression and effects of supportive 113(Suppl):289S–344S. therapy. Neurology 1989;39:475–481. 22. Hamacher J, Buchi S, Georgescu CL, Stammberger U, Thurnheer R, 3. Simonds AK, Muntoni F, Heather S, Fielding S. Impact of nasal ventila- Bloch KE, Weder W, Russi EW. Improved quality of life after lung tion on survival in hypercapnic Duchenne muscular dystrophy. Thorax volume reduction surgery. Eur Respir J 2002;19:54–60. 1998;53:949–952. 23. Natterlund B, Gunnarsson LG, Ahlstrom G. Disability, coping and qual- 4. Eagle M, Baudouin SV, Chandler C, Giddings DR, Bullock R, Bushby ity of life in individuals with muscular dystrophy: a prospective study K. Survival in Duchenne muscular dystrophy: improvements in life over ﬁve years. Disabil Rehabil 2000;22:776–785. expectancy since 1967 and the impact of home nocturnal ventilation. 24. Fitting JW, Paillex R, Hirt L, Aebischer P, Schluep M. Sniff nasal pres- Neuromuscul Disord 2002;12:926–929. sure: a sensitive respiratory test to assess progression of amyotrophic 5. Yasuma F, Konagaya M, Sakai M, Kuru S, Kawamura T. A new lease lateral sclerosis. Ann Neurol 1999;46:887–893. on life for patients with Duchenne muscular dystrophy in Japan. Am 25. Rofﬂer J. Mathilde Escher Heim und Stiftung, Jahresbericht 2001. Zurich: ¨ J Med 2004;117:363. Mathilde Escher Stiftung; 2001.