RISK ASSESSMENT OF NEW FRACTURE FOLLOWING FRAGILITY HIP FRACTURE

RISK ASSESSMENT OF NEW FRACTURE FOLLOWING FRAGILITY HIP FRACTURE

CR. BUDICĂ, ŞT. CRISTEA, GHE. PANAIT

Saint Pantelimon Emergency Hospital, Orthopaedics Department

[email protected]

Summary:

Background: Osteoporosis, a disease with serious socio-economical implication, characterized by bone mass reduction and modifications of internal bone structure, leads to increased bone fragility and to an increased fracture risk. Hip fracture is the major complication of osteoporosis and this appears as a result of a low energy trauma – usually a fall, the bone resistance is over passed by the force applied to the bone.

Aim & Objectives: Our aim was to evaluate the risk of subsequent hip fractures. We have evaluated the incidence of a new fragility fracture; the risk factors associated to a subsequent fracture; the mortality risk and we have also described the modifications of internal bone structure depending on the compliance with osteoporosis treatment. We have consider a subsequent fracture any type of fracture produced after the hip fracture, no matter if is a hip fracture or not (spine, wrist, shoulder, knee). To obtain these results we developed statistical models based on: survival analysis by Kaplan-Meier, life table, COX proportional hazard regression, regression binary logistic.

Study Limitations: Even if the period of time in this study is relatively long (6 years), the number of patients that could be followed for a long period is quite small because some missed their follow-ups, and others couldn’t be reached and so some indicators were excluded from the study.

Results/Findings: The cohort included 300 patients over 60 years with fragility hip fractures admitted and surgically treated at “Saint Pantelimon” Emergency Hospital / Orthopedics Department during 2002-2008. The exclusion standards used were: the patients treated for osteoporosis, patients with cortical-shaft index over 0.5, patients with severe neuropsychical diseases, the patients deceased during hospitalization and also the patients with a T-score >-2.5 (DXA method) or the patients with no diagnosis test for osteoporosis. During the study we used face to face questionnaires, the response rate was 75% (the final group having 300 patients). The patients kept in the study were followed postoperative at 1 month, 3 and 6 months, 12 months, then yearly. Data required for the survival analysis were obtained over the phone from the patient’s family.

Conclusion: The cumulative incidence of subsequent fractures was 7,4% at one year, 16 % at 2 years from the first hip fracture, the median value of refracture being 49 months (CI 95% 32,2-65,8). Men have a greater risk of a new fracture, even though there is no statically significant difference regarding the risk of fracture by gender. The risk of new fracture is higher in younger patients (60-69 years) than the patients over 80 years. The alendronate and vitamin D and Calcium supplements treatment diminishes the risk of a subsequent fracture with approximately 7%. Hip fractures are associated with high mortality. The cumulative incidence of mortality is 2% at one month, 5,4% at 3 months, 17,5% at 6 months, 27,4% at one year and 36,8% at 2 year after the fracture; the median survival time is 35 months. The patients with recurrent fractures have a greater mortality risk than those who didn’t suffer a new fracture. The cumulative incidence of deaths in patients who refractured is 31% at one year. Prevention of the first hip fracture is ideal, but at least after the first fracture the awareness of the physicians should be heightened to prevent future fracture by modifying the risks, which must include optimal management of other medical diagnoses as well as fall prevention.

Keywords: hip fracture, predictors, mortality, fracture risk, osteoporosis, alendronate treatment, accidental falls.

L’évaluation du risque d’une nouvelle fracture après une fracture de fragilité de la hanche

Introduction: L’ostéoporose, une maladie avec des graves implications socio-économiques, caractérisé par la réduction de la masse osseuse et changements de la structure interne osseuse, conduit à une fragilité osseuse augmentée et un risque élevé de fracture. La fracture de la hanche est la majeure complication de l’ostéoporose et elle vient de se produire après un traumatisme à faible énergie – habituellement une chute accidentelle, la résistance osseuse est surmontée par la force appliqué aux os.

Objectifs: Notre objectif a été d’évaluer le risque de fractures ultérieures de la hanche. Nous avons évalué l’incidence d’une nouvelle fracture de la hanche; les facteurs de risque associés a une fracture ultérieure; le risque de la mortalité et nous avons aussi décrit les changements de la structure interne osseuse dépendent de la conformité avec le traitement de l’ostéoporose. Nous avons considéré une fracture ultérieure n’importe quoi type de fracture qui se produit après une fracture de la hanche, peu importe s’il est ou non une fracture de la hanche (colonne vertébrale, poignet, épaule, du genou). Pour obtenir ces résultants nous avons développé des modèles statistiques bases sur : courbes de survie de Kaplan-Meier, table de mortalité, la régression de Cox à risques proportionnels, régression logistique binaire.

Limitées: Même si l’intervalle du temps dans cet étude est relativement long (6 années), le nombre des sujets qui on pu être poursuivis est assez bas parce que quelques sujets ont manqué leurs contrôles, et autres n’ont pu être contactés, et ainsi quelque indicateurs ont été exclus de l’étude.

Résultats: La cohorte contient 300 sujets de plus de 60 ans avec une fracture de fragilité de la hanche hospitalisés et traités chirurgicalement aux L’hôpital d’urgence Saint Pantelimon section d’Orthopédie pendant 2002-2008. Les critères d’exclusion utilisés ont été : les sujets traités pour ostéoporose, les sujets avec un index cortico-diaphysaire plus de 0,5, les sujets avec des graves maladies neuropsychologiques, les sujets qui sont décédés pendant l’hospitalisation et aussi les patients avec un T-score > -2,5 (méthode DXA) ou les patients avec aucun test diagnostique pour l’ostéoporose. Pendant l’étude nous avons utilisé des questionnaires face to face and le taux de réponse a été 75% (le groupe final ayant 300 sujets). Les sujets dans nôtre étude ont été contrôlés postopératoire à un mois, 3 et 6 mois, 12 mois, après annuel. Les informations nécessaires pour l’analyse de la survie ont été obtenues par téléphone par la famille du sujet.

Conclusions: L’incidence cumulative de fractures ultérieures était 7,4% à 1 année, 16% à 2 ans à partir de la première fracture de la hanche, la valeur médiane de la refracture étaient 49 mois (CI 95% 32,2-65,8). Les hommes ont un risque plus grand d’une nouvelle fracture, même si il n’y a pas une différence significative en ce qui concerne le risque de fracture par gendre. Le risque d’une nouvelle fracture est plus grand dans les sujets plus jeunes (60-69ans) que les patients de plus de 80 ans. Le traitement avec alendronate et vitamine D et suppléments de Ca diminue le risque de fracture ultérieure avec 7%. Les fractures de la hanche sont associées avec une grande mortalité. L’incidence cumulative de la mortalité est de 2% à 1 mois, 5,4% à 3 mois, 17,5% à 6 mois, 27,4% à 1 année et 2 années après la fracture ; le temps médian de survie est de 35 mois. Les sujets avec des fractures récurrentes ont un risque de mortalité plus grand que ceux qui n’ont pas une nouvelle fracture. L’incidence cumulative de morts aux patients qui ont réfracturé est de 31% à 1 année. La prévention de la première fracture de la hanche est idéale, mais même après la première fracture la sensibilisation du médecin devait être augmentée pour prévenir la fracture dans l’avenir par le changement des risques, qui nécessite une gestion optimale des autres maladies diagnostiqués comme la prévention de la tombée.

Mots clés: fracture de la hanche, mortalité, risque de fracture, ostéoporose, traitement avec alendronate, chute accidentelle.

Background

Osteoporosis, a metabolic disease characterized by bone mass reduction and modifications of internal bone structure, leads to increased bone fragility and to an increased fracture risk. When the proper conditions appear, for example, a low energy trauma – usually a fall, the bone resistance is over-passed by the force applied to the bone, and so the fragility fracture appears, the major complication of osteoporosis.

Osteoporotic fractures create an enormous burden on healthcare budgets. In Europe, direct medical costs for osteoporotic fractures are estimated at more than 36 billion Euros annually. In Romania, the evaluation of the economic burden of fragility fractures is complicated due to the lack of a national fracture registry and standardized tracking systems. There is a national evaluation of fractures made by The National Endoprosthetic Registry, but we don’t know if this evolution is real or complete, this registry recording data from the endoprosthetic specialized centers, data from little centers could be missing.

In Romania, according to the last report to the IOF (International Osteoporosis Foundation) for 2007/2008, from the national population of 21.673.328, at the end of 2006, the population over 50 years was 6.678.533 (30,8%), 3.701.511 (55,4%) women and 2.977.022 (44,6%) men. According to the DRG (Diagnosis Related Group, www.drg.ro) at the end of 2006 were recorded 125.931 hip fractures.

Healthcare costs differ greatly, as do standards of care. However, because hip fractures, unlike vertebral or wrist fractures, almost always result in hospitalization and require surgery in the vast majority of cases, their incidence and related costs are easier to monitor. For example, the average length of hospital stay following a hip fracture is 8 days in Slovakia, 13.9 days in France, and 26 days in the United Kingdom with costs per day of 38 Euros, 720 Euros and 426 Euros respectively. In Romania the cost for a hip fracture in 2006 was 3765.53 ROL (~1200 Euros) according to the DRG.

In Romania osteoporosis is not considered a major healthcare problem, lots of patients with osteoporosis are clueless concerning their condition, despite the fact that they have risk factors who could lead to an early diagnosis of osteoporosis before the appearance of a fragility fracture. Further, in patients who already suffered a fragility fracture, the diagnosis of osteoporosis is frequently neglected, this leading to an increased risk of future fractures. There is also a flawed training of healthcare professionals whom are supposed to diagnose and treat osteoporosis and its complications – fragility fractures - and especially of general practitioners who are supposed to select the patients that should go to a specialist for osteoporosis.

In this context, we decided to evaluate the risk of subsequent hip fractures. This study evaluates the incidence of subsequent fractures, the risk of a subsequent fracture, the mortality risk, and describes the modifications of internal bone structure depending on the compliance with osteoporosis treatment. We consider a subsequent fracture any type of fracture produced after the hip fracture, no matter if is a hip fracture or not (spine, wrist, shoulder, knee).

To obtain these results we developed statistical models based on: survival analysis by Kaplan-Meier, life table, COX proportional hazard regression, regression binary logistic. The survival differences were based on Kaplan-Meier survival curves and for the meaning of the differences the log-rank test was used. The censored events include the individuals who survived till the end of the study and those who were lost during the follow-up, the final event being death. The refracture risk was assessed using the same method: the patients that didn’t suffer a new fracture during the study were censored, and the date when the fracture appeared was the final event. The refracture incidence after a hip fracture was reported in percentages for age groups, gender, types of fracture surgically treated. The level of significance used was p-2.5 (DXA method) or the patients with no diagnosis test for osteoporosis and those with more than 30% non-answers at the questions from the questionnaire.

During the study we used face to face questionnaires for the patients selected based on the standards presented, and the response rate was 75% (the final group having 300 patients). The patients kept in the study were followed postoperative at 1 month, 3 and 6 months, 12 months, then yearly. Data required for the survival analysis were obtained over the phone from the patient’s family.

The methodology proposed is quantitative, investigation based on face to face questionnaire and medical papers analysis. The analysis of medical charts and other relevant medical documents (medical tests, X-rays) provided significant data for the study. These quantitative data were enriched with qualitative data obtained based on patient observation protocols during hospitalization, as well as in follow-ups.

In Table 1 we showed the main characteristics of the studied group:

Table 1. Socio-demographic and medical characteristics of the studied group

Age (years) No. (%)

60-69 53 (18)

70-79 127 (42)

80-89 94 (31)

90+ 26 (9)

Mean / Median 78 (77)

Minimum – Maximum / Std. Deviation 60 – 96 (9)

Women 248 (83)

Fracture type and treatment option

Pertrochanteric fractures 140 (47)

DHS 140 (100)

Femoral neck fractures 120 (40)

Internal fixation 40 (33)

Unipolar hemiarthroplasty 40 (33)

Bipolar hemiarthroplasty 2 (1)

Total hip arthroplasty 38 (33)

Subtrochanteric fractures 40 (13)

DHS 20 (50)

Gamma nail 20 (50)

Comorbidities

Cardiovascular diseases 213 (71)

Digestive affections 126 (42)

Rheumatic affections 124 (41)

Neuropsychical affections 110 (37)

Endocrine and metabolic diseases 68 (23)

Anemia 83 (28)

Pulmonary affections 40 (13)

Neoplasia 8 (3)

Treatment (mean) 1,27

Minimum – Maximum / Std. Deviation 0-5 (1)

Medical postfracture complications

Cardiac complications 23 (8)

Pulmonary complications 12 (4)

Independence in activities of daily living (prefracture)

Independents 139 (46)

Need some help 111 (37)

Dependents 50 (17)

Exercise (+ 30 min / day) 170 (61)

Fall frequency

Rarely 52 (18)

Several times 91 (32)

Many times 70 (25)

Frequently 69 (25)

House factors risk score

0 52 (17)

1 133 (44)

2 86 (29)

3 25 (8)

4 4 (1)

Compliance with alendronate, Ca and vitamin D treatment 57 (35)

Self-evaluation of health status

Good 37 (13)

Medium 85 (31)

Bad 154 (56)

Pain 87 (53)

Concerning comorbidities, in the neurological affections category we included: Parkinson’s disease, paralyses, dementia (Alzheimer’s disease, cerebral atherosclerosis, confusive state), stroke, depressions and epilepsy. The rheumatic affections category include rheumatoid arthritis and arthrosis. Hyperthyroidism, hyperparathyroidism, Cushing’s syndrome, hypothyroidism, diabetes mellitus, endocrine causes of nulliparity are included in the category of endocrine diseases. In the digestive affections category we included hepatic diseases (chronic hepatitis, cirrhosis), intestinal affections that generates malabsorbtion, gastric affections (gastric and duodenal ulcer, gastroesophageal reflux disease). Cardiovascular diseases are represented by arterial hypertension, chronic heart failure, chronic ischemic cardiomyopathy, cardiac arrhythmia. Pulmonary diseases are represented by chronic obstructive bronchopneumopathy, bronchic astma, pulmonary tuberculosis, and neoplasia category include prostate cancer, cervical cancer, breast cancer, lung cancer and leukemias.

In the independents category we included those patients who were able to perform alone basic activities of daily living (dressing, bathing, feeding, going to the toilet), instrumental activities such as shopping, cooking, cleaning, using public transportation, housework. The patients who are able to perform activities of daily living, but need assistance to ambulate in the community, were included in the middle category (need some help). As dependents we classified those who can’t perform activities of daily living.

In the analysis of living conditions, concerning the refracture risk we regarded the following characteristics: poor illumination of the house, high aprons between rooms, slippery floor and abrupt staircase without rail.

To determine the frequency of the falls we asked the patients to quantify de number of falls suffered in the last 12 months before the hip fracture on a scale with 4 degrees : rarely or none, several times, many times, frequently. From the clinical point of view we were interested in sorting the frequency of the falls between „a fall” (rarely) and „recurrent falls” (several times, many times, frequently).

By the compliance with osteoporosis treatment we understood the persistence for one year of alendronate, Calcium supplements and vitamin D treatment. This indicator was measured 1 year after the hip fracture. Also after 1 year the patients were asked if they experienced acute pain in the postfracture period.

Our study has some methodological limitations. Even if the period of time in this study is relatively long (6 years), the number of patients that could be followed for a long period is quite small because some missed their follow-ups, and others couldn’t be reached and so some indicators were excluded from the study. Therefore, one year after the fracture just a little over half patients remained (165), and this fact affects the refracture prognosis. Further, the results obtained must be interpreted with prudence because not all of the statistical indicators are significant for the level of significance p