Epidemiological characteristics of osteoarticular tuberculosis in Henan Province, China, 2019–2023: a multicenter retrospective study

Tuberculosis is a disease most people associate with the lungs, a persistent cough, and the need for fresh air. Yet the bacteria that cause it, Mycobacterium tuberculosis, are opportunistic travelers. Once inside the body, they can settle in almost any organ, from the brain to the kidneys. When these microscopic invaders take up residence in the bones and joints, the condition is known as osteoarticular tuberculosis. Unlike a simple sprain or arthritis, this is a chronic infection that slowly eats away at the skeleton. Because the damage happens quietly over months or years, it often goes unnoticed until it is too late, leaving patients with permanent deformities, nerve damage, or even paralysis. In a country as vast and populous as China, understanding exactly who gets sick, where the disease hides, and how it spreads is essential for stopping it before it causes irreversible harm.

Researchers in Henan Province, a central region of China with a massive population, recently set out to map the landscape of this specific form of the disease. They looked back at the medical records of more than 3,200 patients who were newly diagnosed with bone and joint tuberculosis between 2019 and 2023. These patients had been treated at three major hospitals that serve as referral centers for the entire province. By piecing together the stories of these individuals, the team built a clear picture of the disease's behavior in a real-world setting, moving beyond general theories to see the actual faces and lives behind the statistics.

The first thing the data revealed was who is most likely to be affected. The disease does not strike randomly; it favors middle-aged and older adults, with the average patient being nearly 48 years old. The group most heavily hit was people between 51 and 70 years old, though a smaller, noticeable spike occurred among young adults in their twenties. Men were significantly more likely to be diagnosed than women, outnumbering them by about three to two. When the researchers looked at what these patients did for a living, one group stood out: farmers. Nearly half of all the patients were farmers, a proportion far higher than any other occupation. This suggests that the physical demands of farm work, combined with potential delays in seeking medical care in rural areas, may create a perfect storm for the disease to take hold.

Where these patients lived also told a story, though with a slight twist. The majority of cases came from the central and northern parts of Henan. However, the researchers were careful to note that this pattern might not reflect the true spread of the disease across the entire province. Because the study relied on patients who traveled to specific major hospitals in cities like Zhengzhou and Xinxiang, the results likely show where people went for help rather than exactly where the bacteria are most common. It is possible that people in other regions simply did not have access to the same level of specialized care or did not travel as far to get it.

When the researchers examined the specific parts of the body under attack, the spine emerged as the primary target. More than three-quarters of the patients had tuberculosis in their spinal column. Within the spine, the lower back was the most frequent site of infection, followed by the middle section. This is a critical finding because spinal tuberculosis is the most dangerous form of the disease; if left untreated, it can collapse the vertebrae and crush the spinal cord, leading to paralysis. In this group of patients, about 167 individuals had already developed some degree of paralysis, a tragic outcome that underscores the need for earlier detection. While the spine was the main battleground, the disease also attacked the joints, with the knee and hip being the most common sites outside the spine.

The study also highlighted that this bone infection rarely travels alone. In more than 40 percent of the cases, the patients also had active tuberculosis in their lungs. This connection suggests that for many, the infection started in the chest and then traveled through the bloodstream to settle in the bones. The likelihood of having both lung and bone disease varied by age; it was particularly common in teenagers and young adults, where more than half of the patients had lung involvement. Beyond the lungs, the bacteria had also spread to other parts of the body in about one-fifth of the patients, affecting the lymph nodes, the brain, or the urinary system.

The researchers also looked at the health of the patients before they were diagnosed with tuberculosis. They found that a significant number of these individuals were already fighting other battles. More than 13 percent had diabetes, a condition that weakens the body's ability to fight off infections. A smaller but notable group had HIV, the virus that attacks the immune system. Additionally, many patients showed signs of malnutrition, such as low levels of protein in their blood or anemia, which are common side effects of a long, draining illness. These underlying health issues likely made the patients more vulnerable to the tuberculosis bacteria and may have made the disease harder to treat.

Looking at the timeline of the study, the number of new cases fluctuated. The count started high in 2019, dropped in the following years, hit a low point in 2022, and then began to rise again in 2023. The researchers suspect that the dip during the middle of the study period might be linked to the global pandemic, when people were less likely to leave their homes or visit hospitals. The slight increase in 2023 suggests that as normal life returned, so did the risk of transmission.

Ultimately, this study paints a portrait of a disease that is still very much alive in central China, targeting specific groups of people and striking with a preference for the spine. It confirms that osteoarticular tuberculosis is not just a rare curiosity but a significant public health challenge that disproportionately affects farmers, men, and older adults. The findings suggest that doctors need to be more vigilant, especially when seeing patients with back pain or joint swelling who also have risk factors like diabetes or a history of lung issues. By recognizing the patterns of who gets sick and where the disease hides, health officials can work toward catching these infections earlier, before they have the chance to cause permanent damage.