The non-silent epidemic: low back pain as a primary cause of hospitalisation
Low back pain (LBP) is the most common cause of pain in adults and the second health condition that prompts patients to seek ambulatory medical care visits. To analyse the impact of LBP on hospitalisations in healthcare facilities within the official subsector in Argentina between 2006 and 2010. Discharges in which the original diagnosis had been either adult LBP or lumbosciatica were assessed. The data comprised age, gender, province of residence, average length of stay (LOS) in the hospital, intra-hospital death, and the Provincial Human Development Index (PHDI). 17,859 discharges had an original diagnosis of LBP and 10,948 of lumbosciatica, which jointly accounted for 18.7 % of all the discharges documented for Diseases of Osteomuscular System and Connective Tissue (DOMS). Hospital discharges of female patients represented 53.7 %. The average age upon admission was 47.7 years in men versus 47.9 in women. The average LOS was slightly higher in men (4.2 vs. 3.8 days, p 0.01). In provinces with a PHDI below the national average, a surgical procedure was performed in 3.1 % of the discharges versus 4.1 % in the provinces with a PHDI above the national average (p < 0.001). LBP was the most frequent cause of hospitalisation due to DOMS. It occurred with a slightly higher frequency in women and prompted short hospitalisations. A surgical procedure was carried out during hospitalisation in very few cases, but the percentage of surgeries during hospitalisation was higher in provinces with a PHDI above the national average.
KeywordsLow back painHospitalisationsProvincial Human Development IndexSurgical procedure
Low back pain (LBP) is the most common cause of pain in adults and the second health condition (only after upper respiratory tract infections) that prompts patients to seek ambulatory medical care visits. One-fourth of the adults have had at least 1 day of LBP in the three previous months, and 65–80 % of adults sustain LBP at some point of their lives [1–4].
LBP alters the patients’ quality of life, and its huge direct and indirect costs have a significant impact on patients, their families, the community, the labour market, and the healthcare system [4–7].
LBP used to be one of the most frequent causes of hospitalisation in the USA, and though a dramatic decrease in the number of hospitalisations due to non-surgically treatable LBP was observed between 1979 and 1990 , the proportion of ambulatory medical care visits triggered by this condition has remained relatively stable . Conversely, the percentage of surgeries to treat LBP, particularly the spinal fusion, seems to be on the rise [2, 8].
Epidemiological data suggest that the prevalence of LBP in Latin America is as high as it is in developed countries , and therefore, it may be suspected of being a relevant cause of hospitalisation. If that were actually the case, it would be important to analyse whether the trend towards a higher number of surgeries observed in developed countries can also be seen in Latin America, and whether there are regional differences given the economic inequality among provinces even within the same country.
The goal of this study was to analyse the impact of LBP on hospitalisations in healthcare facilities within the official subsector in Argentina between 2006 and 2010.
Materials and methods
Every discharge in Argentina between 2006 and 2010 was analysed by means of the data afforded by the Statistics and Information Department of the Ministry of Health of the Argentine Republic. (Diseases of Osteomuscular System and Connective Tissue/DOMS. International Classification of Diseases, Tenth Revision: M001-999).
The discharges in which the main diagnosis was either adult LBP or lumbosciatica (18 years old or more) were selected (Codes CIE 10: M 545 y M 544).
The database includes all the cases the official subsector has come across, and it is generated through the hospitalisation reports that every hospital in the public subsector in the country must complete (coded) irrespective of its level of complexity. That was why it was not possible to explore other data of interest about the condition (duration), the patients (level of education, socioeconomic status) and the outcome (type of surgery, reason for surgery, cause of death).
The information encompassed in the database analysed by the authors is anonymous, it identifies discharges, not patients, and it is part of the data gathered by the Ministry of Health of the Argentine Republic on a regular basis to generate national vital statistics. Consequently, authorisation from an ethics committee was not required to write this report.
Therefore, a patient that was discharged twice will be listed twice. The diagnosis was based on the physician’s clinical judgment, and the reports were completed in accordance with the Health Statistics System.
The Ministry of Health of the Argentine Republic periodically reports discharge data by diagnosis clusters (e.g. Diseases of Osteomuscular System and Connective Tissue), but it does not carry out a detailed analysis for each rheumatic disease. Although there is some previous partial information collected every 5 years, this report contains the first complete data for the whole country for a five-year period (2006–2010).
For the time being, only a few provinces account for the secondary causes of hospital discharges. Hence, for this first report, it was determined that only primary causes of hospitalisation were worth analysing.
Discharges in which the original diagnosis was osteoarthritis, infections, inflammatory spondyloarthropathies, discopathies and tumours were excluded from this study and are reported elsewhere.
The information was derived from healthcare facilities within the official subsector—National, Provincial and Municipal Departments—so private healthcare centres, health insurance clinics and some university hospitals were excluded.
The data were analysed by age, gender and province of residence. Average length of stay (LOS) in the hospital in days and intra-hospital death were analysed as well.
Discharges in which the original diagnosis had been either LBP or lumbosciatica were divided in: (a) the ones from provinces with a Provincial Human Development Index (PHDI) above the national average, and (b) the ones from provinces with a PHDI below the national average. According to the data from the United Nations Development Programme, the national average of the PHDI for 2009 was 0.830.
The Human Development Index (HDI) is a compound index that appraises the average income of a country and examines health, education and wealth figures. The estimate of the PHDI includes the three basic dimensions of HDI with only one difference: instead of gross domestic product per capita (GDP), household income per capita is employed as an indicator of access to resources .
Descriptive statistics were applied for the general analysis. Means were compared by utilising Student’s t test. The nominal variables were compared by means of the Chi-square test or Fisher’s exact test as applicable. A p < 0.05 was considered statistically significant in two-tailed tests. Both Windows Excel and EPI info version 3.5.4. were used for the statistical analysis.
Discharges of patients with major diseases of osteomuscular system and connective tissue, Argentina 2006–2010
Total and % of discharges
Average length of stay (in days)
Low back pain/ Lumbosciatica
Systemic lupus erythematosusc
Hospital discharges of female patients represented 53.7 % of the total. The average age upon discharge was 47.8 years old (age range 18–107 years old). The average age upon admission was 47.7 years old in men versus 47.9 years old in women (p 0.5).
The average LOS in the hospital was 3.8 days. It was slightly higher in men than in women (4.2 vs. 3.8 days, respectively; p 0.01).
A surgical procedure was performed during hospitalisation in 2.8 % of the discharges, with similar proportion in men and women. In 16 % of the discharges, this information was not provided. The average age of the female patients who underwent a surgical procedure was slightly higher than that of the male patients who went through surgery (48.3 vs. 47.6 years old, respectively; p 0.6).
Intra-hospital mortality was 0.17 %, a tad higher in men (0.19 vs. 0.15 %); although these differences were not statistically significant (p 0.4). In 7.5 % of all the discharges, this information was not supplied. No statistically significant differences were observed as for the average age of men and women who passed away (59.2 vs. 58.8 years old, respectively; p 0.9).
When discharges were analysed according to PHDI, it was noticed that 21,243 discharges (73.7 %) were reported by provinces below the national average, 7104 discharges (24.7 %) were reported by provinces above the national average, and 460 discharges (1.6 %) lacked the place of residence.
The patients’ average age was 47.1 years old in provinces with a PHDI above the national average versus 48.1 years old in provinces with a PHDI below the national average (p < 0.001), and the LOS in the hospital was 4.1 and 3.9 days, respectively (p 0.2).
The provinces with a PHDI above the national average reported surgical procedures during hospitalisation in 4.1 % of the discharges versus 2.4 % in the rest of the provinces. This information must be taken with a grain of salt since this figure was not provided in 21.4 % of the discharges of those provinces with a PHDI below the national average. The missing information corresponds mostly to the province of Buenos Aires for the years 2006–2009. However, in 2010, Buenos Aires reported a 2.6 % of surgical procedures during hospitalisation. If the missing information is not taken into account, a surgical procedure was performed in 4.1 % of the discharges in the provinces with a PHDI above the national average versus 3.1 % in the provinces with a PHDI below the national average (p < 0.001).
Nonetheless, LBP should not go unnoticed due to its prevalence, its morbidity and its economic impact: patients who experience LBP are extremely frequent outpatients, and their condition results in a great deal of ambulatory medical care visits, both in private settings and emergency rooms, and as seen in this report, accounts for almost 20 % of all hospitalisations attributable to DOMS in Argentina.
While in most cases, LBP is self-limiting, when it is chronic, patients become highly demanding of the healthcare system. Approximately 5 % of the patients with disability due to LBP account for 75 % of the costs of this condition .
The usual mistake is to consider LBP as a primarily surgical problem. Ordinarily, surgery is not a therapeutic option for acute idiopathic LBP . Although the final data of this study may be biased by a significant amount of missing information, a surgical procedure during hospitalisation was performed only in 3–4 % of the cases.
According to some studies, the prevalence of LBP is lower among people with higher level of education and better income [2, 6]. However, some other studies claim that neither the level of education nor the income seems to have any sort of bearing on LBP duration and return to work [15–17].
In this study, it was observed that the percentage of surgical procedures was significantly higher in provinces with a PHDI above the national average. This fact is likely to be related to more readily access to specialists and high-complexity imaging studies in favoured areas.
This study has several limitations. The focus of analysis was the number of discharges, not the number of patients; hence, it is possible that some patients with unremitting LBP were hospitalised more than once.
The data were anonymous, and access to the patients’ medical charts was not granted, so it was feasible neither to corroborate the diagnosis nor to assess what the attending physician’s rationale was both to make such diagnosis and to determine the risk factors for hospitalisation owing to low back pain. In some cases, the initial diagnosis of LBP may have changed during follow-up or after a study carried out on an outpatient basis.
Although the percentage of hospital discharges in which a surgery was performed during hospitalisation was reported, information regarding the type of surgery and the outcomes of such surgeries has not been provided.
Nonetheless, in 80–85 % of the cases of low back pain, it is not possible to find a definite treatable cause [1, 7]. Besides, discharges in which the original diagnosis was osteoarthritis, infections, inflammatory spondyloarthropathies, discopathies and tumours have been excluded from this study, and are reported elsewhere.
Since the data come from the official subsector, whose involvement in the population’s health coverage varies substantially among districts, it was not possible to calculate rates.
Despite the above-mentioned limitations, this study is based on the hospitalisation reports and includes all the cases registered in the official subsector which provide information based on the clinical diagnosis (coded), as well as age, gender, LOS in the hospital and hospitalisation location. As this record is submitted on a yearly basis, it enables authorities to make short- and medium-term projections to estimate needs and the use of public services and may be complemented with other sources of information like surveys, prevalence studies and employee absenteeism studies.
Both the prevalence and the impact of LBP on public health have been broadly studied in developed countries.
Most published studies about LBP in Latin America focus on its prevalence and the associated risk factors, and yield variable results . However, the prevalence of LBP in the South of Latin America appears to be as high as in the USA, and its impact is expected to grow even more in the next decades due to the rising life expectancy of the population .
LBP was the most frequent cause of hospitalisation due to DOMS in Argentina between 2006 and 2010. It occurred with a slightly higher frequency in women, and prompted short hospitalisations.
A surgical procedure was carried out during hospitalisation in very few cases, but the percentage of surgeries during hospitalisation was higher in provinces with a PHDI above the national average.
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Compliance with ethical standards
Conflict of interest
The authors declare that there is no conflict of interest’.