Treating osteoporosis

Who is treated, and who is monitored

Not everyone with low bone density needs medication. The decision follows risk:

• High and very-high risk patients — those with osteoporosis by T-score, a fragility fracture, or high FRAX probability — should be treated to prevent a first or recurrent fracture.
• Low-to-moderate risk patients are generally monitored and reassessed over time, with attention to calcium, vitamin D, exercise, and fall prevention (see Nutrition & Life).

Everyone — treated or not — should have adequate calcium and vitamin D, which is the foundation on which every osteoporosis medicine is built, not a treatment in itself for high-risk disease.

Antiresorptive therapies — preserving bone

Antiresorptive drugs slow the osteoclasts that remove bone, tipping the remodeling balance back toward preservation. They are effective, widely available, and first-line for most patients at high (but not very high) risk.

Anabolic (bone-building) therapies

Anabolic agents do something antiresorptives cannot: they stimulate new bone formation, adding bone rather than just slowing its loss. Studies over the past decade show anabolic agents produce faster and larger reductions in fracture risk and gains in bone density than antiresorptives — and head-to-head trials in high-risk patients show they prevent fractures more effectively than bisphosphonates and denosumab. This is the "bone-building" case at the heart of modern high-risk care.

Goal-directed treatment & sequencing

The most important shift in osteoporosis care is moving from "same first drug for everyone" to a goal-directed, treat-to-target approach — the subject of the 2024 ASBMR/BHOF task force position statement. Three ideas drive it:

• Set a target. The bone-density level a patient reaches on treatment predicts their future fracture risk. Total-hip BMD is the most useful target because it predicts both vertebral and nonvertebral fractures; a T-score above −2.5 is a reasonable minimum goal for most.
• Match the first drug to the goal. Choose the initial therapy by how likely it is to reach the target in a reasonable time — which depends on the starting T-score. A patient far below target is unlikely to get there on a bisphosphonate alone and is better served starting with an anabolic.
• Order matters — anabolic first. Starting with an anabolic and then an antiresorptive produces greater bone-density gains, particularly at the hip, than the reverse order. The gains from an anabolic are lost if not followed by an antiresorptive to maintain them.

How likely is a target to be reached? Analyses give concrete numbers. With denosumab, a woman starting with a total-hip T-score of −2.7 has about a 71% chance of reaching a T-score above −2.5 in three years; at −3.0 that falls to ~12%, and at −3.5 it is near zero — though longer treatment raises the odds. Anabolic agents reach targets from lower starting points more often. This is exactly the kind of estimate that should guide the first choice, not trial and error.

Drug holidays & stopping treatment

Osteoporosis is lifelong, but not every drug is taken forever — and how a drug is stopped matters as much as how it's started.

• Bisphosphonates can allow a "drug holiday" after several years in appropriately selected lower-risk patients, because their effect lingers in bone. But it isn't indefinite: after stopping long-term alendronate, bone-turnover markers rise and BMD begins to fall within the first year, so patients on a holiday need continued monitoring and a plan to restart.
• Denosumab is different — it has no holiday. Stopping it (or even delaying a dose) causes rapid bone loss and a rebound in vertebral fracture risk, sometimes multiple fractures. If denosumab is discontinued, it must be followed by a bisphosphonate (or another agent) to prevent this.
• Anabolic courses are time-limited by design (~1–2 years) and are always followed by an antiresorptive to preserve the bone that was built.

How we grade evidence. Every therapy carries a plain label — from established, guideline-supported care (A) through moderate (B) and conflicting (C) to experimental (D) and insufficient (E). A change in bone density or a laboratory marker is not the same as a demonstrated reduction in fractures, and we say which we mean.